Publications – Michał Parniak

@article{Borówka2025,

title = {Optically-biased Rydberg microwave receiver enabled by hybrid nonlinear interferometry},

author = {Sebastian Borówka and Mateusz Mazelanik and Wojciech Wasilewski and Michał Parniak},

doi = {10.1038/s41467-025-63951-9},

issn = {2041-1723},

year  = {2025},

date = {2025-12-00},

urldate = {2025-12-00},

journal = {Nat Commun},

volume = {16},

number = {1},

publisher = {Springer Science and Business Media LLC},

abstract = {<jats:title>Abstract</jats:title>

          <jats:p>Coupling a Rydberg vapour medium to both microwave and optical fields enables the benefits of all-optical detection, such as minimal disturbance of the measured field and resilience to very strong signals, since no conventional antenna is required. However, peak sensitivity typically relies on adding a microwave local oscillator, which compromises the all-optical nature of the measurement. Here we introduce an alternative, <jats:italic>optical-bias detection</jats:italic>, that maintains fully optical operation while achieving high sensitivity. To address laser phase noise, which is critical in this approach, we perform a simultaneous measurement of the noise using a nonlinear process and correct it in real time via data processing. This yields a 35 dB improvement in signal-to-noise ratio compared with the basic method. We demonstrate a sensitivity of <jats:inline-formula>

              <jats:alternatives>

                <jats:tex-math>$$176,{{{rm{nV}}}}/{{{rm{cm}}}}/sqrt{{{{rm{Hz}}}}}$$</jats:tex-math>

                <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">

                  <mml:mn>176</mml:mn>

                  <mml:mspace/>

                  <mml:mi>nV</mml:mi>

                  <mml:mo>/</mml:mo>

                  <mml:mi>cm</mml:mi>

                  <mml:mo>/</mml:mo>

                  <mml:msqrt>

                    <mml:mrow>

                      <mml:mi>Hz</mml:mi>

                    </mml:mrow>

                  </mml:msqrt>

                </mml:math>

              </jats:alternatives>

            </jats:inline-formula>, reliable operation up to 3.5 mV/cm at 13.9 GHz, and quadrature-amplitude modulated data transmission, underlining the ability to detect microwave field quadratures while preserving the unique advantages of all-optical detection.</jats:p>},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nowosielski2025,

title = {Superheterodyne Rydberg S-band receiver with a multi-tone local oscillator based on an atomic transition loop},

author = {Jan Nowosielski and Mateusz Mazelanik and Wojciech Wasilewski and Michal Parniak},

doi = {10.1364/ao.557585},

issn = {2155-3165},

year  = {2025},

date = {2025-06-17},

urldate = {2025-06-17},

journal = {Appl. Opt.},

publisher = {Optica Publishing Group},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kasza2025,

title = {Atomic-optical interferometry in fractured loops: A general solution for Rydberg radio-frequency receivers},

author = {Bartosz Kasza and Sebastian Borówka and Wojciech Wasilewski and Michał Parniak},

doi = {10.1103/physreva.111.053718},

issn = {2469-9934},

year  = {2025},

date = {2025-05-00},

urldate = {2025-05-00},

journal = {Phys. Rev. A},

volume = {111},

number = {5},

publisher = {American Physical Society (APS)},

abstract = {<jats:p>The development of novel radio-frequency atomic receivers has brought attention to the theoretical description of atom-light interactions in sophisticated multilevel schemes. Of special interest are schemes where several interaction paths interfere with each other, bringing about the phase-sensitive measurement of detected radio fields. In the theoretical modeling of those cases, the common assumptions are often insufficient to determine the boundary detection parameters, such as the receiving bandwidth or saturation point, critical for practical considerations of atomic sensing technology. This evokes the resurfacing of the long-standing problem on how to describe an atom-light interaction in a fractured loop. In such a case, the quantum steady state is not achieved even with constant, continuous interactions. Here we propose a method for modeling such a system, basing our approach on the Fourier expansion of a nonequilibrium steady state. The proposed solution is both numerically effective and able to predict edge cases, such as saturation. Furthermore, as an example, we employ this method to provide a complete description of a Rydberg superheterodyne receiver, obtaining the boundary parameters describing the operation of this atomic detector.</jats:p>

          <jats:sec>

            <jats:title/>

            <jats:supplementary-material>

              <jats:permissions>

                <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement>

                <jats:copyright-year>2025</jats:copyright-year>

              </jats:permissions>

            </jats:supplementary-material>

          </jats:sec>},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Galinskiy2024,

title = {Nonclassical Correlations between Photons and Phonons of Center-of-Mass Motion of a Mechanical Oscillator},

author = {Ivan Galinskiy and Georg Enzian and Michał Parniak and Eugene S. Polzik},

doi = {10.1103/physrevlett.133.173605},

issn = {1079-7114},

year  = {2024},

date = {2024-10-00},

urldate = {2024-10-00},

journal = {Phys. Rev. Lett.},

volume = {133},

number = {17},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Borówka2024,

title = {Rydberg-atom-based system for benchmarking millimeter-wave automotive radar chips},

author = {Sebastian Borówka and Wiktor Krokosz and Mateusz Mazelanik and Wojciech Wasilewski and Michał Parniak},

doi = {10.1103/physrevapplied.22.034067},

issn = {2331-7019},

year  = {2024},

date = {2024-09-00},

urldate = {2024-09-00},

journal = {Phys. Rev. Applied},

volume = {22},

number = {3},

publisher = {American Physical Society (APS)},

abstract = {<jats:p>Rydberg atomic sensors and receivers have enabled sensitive and traceable measurements of rf fields at a wide range of frequencies. Here, we demonstrate the detection of electric field amplitude in the extremely-high-frequency (EHF) band, at <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><a:mn>131</a:mn><a:mspace width="0.2em"/><a:mi>GHz</a:mi></a:math>. In our approach, we propagate the EHF field in a beam, with control over its direction and polarization at the detector using photonic wave plates. This way, we take advantage of the highest detection sensitivity, registered for collinear propagation and circular polarization. To exhibit the potential for applications in this kind of Rydberg-atom-based detection, we perform test measurements on the EHF field emitted from an on-chip radar, which is designed to be used in the automotive industry as a vital sign detector. Our work elucidates practical applications of Rydberg-atom media and photonic metamaterial elements.</jats:p>

          <jats:sec>

            <jats:title/>

            <jats:supplementary-material>

              <jats:permissions>

                <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement>

                <jats:copyright-year>2024</jats:copyright-year>

              </jats:permissions>

            </jats:supplementary-material>

          </jats:sec>},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kurzyna2024,

title = {Long-lived collective Rydberg excitations in atomic gas achieved via ac-Stark lattice modulation},

author = {Stanisław Kurzyna and Bartosz Niewelt and Mateusz Mazelanik and Wojciech Wasilewski and Michał Parniak},

doi = {10.22331/q-2024-08-02-1431},

issn = {2521-327X},

year  = {2024},

date = {2024-08-02},

urldate = {2024-08-02},

journal = {Quantum},

volume = {8},

publisher = {Verein zur Forderung des Open Access Publizierens in den Quantenwissenschaften},

abstract = {<jats:p>Collective Rydberg excitations provide promising applications ranging from quantum information processing, and quantum computing to ultra-sensitive electrometry. However, their short lifetime is an immense obstacle in real-life scenarios. The state-of-the-art methods of prolonging the lifetime were mainly implemented for ground-state quantum memories and would require a redesign to effectively work on different atomic transitions. We propose a protocol for extending the Rydberg excitation lifetime, which in principle can freeze the spin-wave and completely cancel the effects of thermal dephasing. The protocol employs off-resonant ac-Stark lattice modulation of spin waves by interfering two laser beams on the atomic medium. Our implementation showed that the excitation lifetime can be extended by an order of magnitude, paving the way towards more complex protocols for collective Rydberg excitations.</jats:p>},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nowosielski2024,

title = {A warm Rydberg atom-based quadrature amplitude-modulated receiver},

author = {Jan Nowosielski and Marcin Jastrzebski and Pavel Halavach and Karol Lukanowski and Marcin Jarzyna and Mateusz Mazelanik and Wojciech Wasilewski and Michal Parniak},

doi = {10.1364/oe.529977},

issn = {1094-4087},

year  = {2024},

date = {2024-07-25},

urldate = {2024-07-25},

journal = {Opt. Express},

publisher = {Optica Publishing Group},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Borówka2023,

title = {Continuous wideband microwave-to-optical converter based on room-temperature Rydberg atoms},

author = {Sebastian Borówka and Uliana Pylypenko and Mateusz Mazelanik and Michał Parniak},

doi = {10.1038/s41566-023-01295-w},

issn = {1749-4893},

year  = {2024},

date = {2024-01-00},

journal = {Nat. Photon.},

volume = {18},

number = {1},

pages = {32--38},

publisher = {Springer Science and Business Media LLC},

abstract = {AbstractThe coupling of microwave and optical systems presents an immense challenge due to the natural incompatibility of energies, but potential applications range from optical interconnects for quantum computers to next-generation quantum microwave sensors, detectors and coherent imagers. Several of the engineered platforms that have emerged are constrained by specific conditions, such as cryogenic environments, impulse protocols or narrowband fields. Here we employ Rydberg atoms that allow the wideband coupling of optical and microwave photons at room temperature with the use of a modest set-up. We present continuous-wave conversion of a 13.9 GHz field to a near-infrared optical signal using an ensemble of Rydberg atoms via a free-space six-wave mixing process designed to minimize noise interference from any nearby frequencies. The Rydberg photonic converter exhibits a conversion dynamic range of 57 dB and a wide conversion bandwidth of 16 MHz. Using photon counting, we demonstrate the readout of photons of free-space 300 K thermal background radiation at 1.59 nV cm−1 rad−1/2 s−1/2 (3.98 nV cm−1 Hz−1/2) with a sensitivity down to 3.8 K of noise-equivalent temperature, allowing us to observe Hanbury Brown and Twiss interference of microwave photons.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Jastrzębski2024,

title = {Spectrum-to-position mapping via programmable spatial dispersion implemented in an optical quantum memory},

author = {Marcin Jastrzębski and Stanisław Kurzyna and Bartosz Niewelt and Mateusz Mazelanik and Wojciech Wasilewski and Michał Parniak},

doi = {10.1103/physreva.109.012418},

issn = {2469-9934},

year  = {2024},

date = {2024-01-00},

urldate = {2024-01-00},

journal = {Phys. Rev. A},

volume = {109},

number = {012418},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Krokosz2024,

title = {Beating the spectroscopic Rayleigh limit via post-processed heterodyne detection},

author = {Wiktor Krokosz and Mateusz Mazelanik and Michał Lipka and Marcin Jarzyna and Wojciech Wasilewski and Konrad Banaszek and Michał Parniak},

doi = {10.1364/ol.514659},

issn = {1539-4794},

year  = {2024},

date = {2024-00-00},

journal = {Opt. Lett.},

volume = {49},

number = {4},

publisher = {Optica Publishing Group},

abstract = {Quantum-inspired superresolution methods surpass the Rayleigh limit in imaging, or the analogous Fourier limit in spectroscopy. This is achieved by carefully extracting the information carried in the emitted optical field by engineered measurements. An alternative to complex experimental setups is to use simple homodyne detection and customized data analysis. We experimentally investigate this method in the time-frequency domain and demonstrate the spectroscopic superresolution for two distinct types of light sources: thermal and phase-averaged coherent states. The experimental results are backed by theoretical predictions based on estimation theory.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lipka2024,

title = {Ultrafast electro-optic time-frequency fractional Fourier imaging at the single-photon level},

author = {Michał Lipka and Michał Parniak},

doi = {10.1364/oe.507911},

issn = {1094-4087},

year  = {2024},

date = {2024-00-00},

journal = {Opt. Express},

volume = {32},

number = {6},

publisher = {Optica Publishing Group},

abstract = {The Fractional Fourier Transform (FRT) corresponds to an arbitrary-angle rotation in the phase space, e.g., the time-frequency (TF) space, and generalizes the fundamentally important Fourier Transform. FRT applications range from classical signal processing (e.g., time-correlated noise optimal filtering) to emerging quantum technologies (e.g., super-resolution TF sensing) which rely on or benefit from coherent low-noise TF operations. Here a versatile low-noise single-photon-compatible implementation of the FRT is presented. Optical TF FRT can be synthesized as a series of a spectral disperser, a time-lens, and another spectral disperser. Relying on the state-of-the-art electro-optic modulators (EOM) for the time-lens, our method avoids added noise inherent to the alternatives based on non-linear optical interactions (such as wave-mixing, cross-phase modulation, or parametric processes). Precise control of the EOM-driving radio-frequency signal enables fast all-electronic control of the FRT angle. In the experiment, we demonstrate FRT angles of up to 1.63 rad for pairs of coherent temporally separated 11.5 ps-wide pulses in the near-infrared (800 nm). We observe a good agreement between the simulated and measured output spectra in the bright-light and single-photon-level regimes, and for a range of pulse separations (20 ps to 26.7 ps). Furthermore, a tradeoff is established between the maximal FRT angle and optical bandwidth, with the current setup accommodating up to 248 GHz of bandwidth. With the ongoing progress in EOM on-chip integration, we envisage excellent scalability and vast applications in all-optical TF processing both in the classical and quantum regimes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lipka2024c,

title = {Super-resolution of ultrafast pulses via spectral inversion},

author = {Michał Lipka and Michał Parniak},

doi = {10.1364/optica.522555},

issn = {2334-2536},

year  = {2024},

date = {2024-00-00},

urldate = {2024-00-00},

journal = {Optica},

volume = {11},

number = {9},

publisher = {Optica Publishing Group},

abstract = {<jats:p>The resolution limits of classical spectroscopy can be surpassed by

					quantum-inspired methods leveraging the information contained in the

					phase of the complex electromagnetic field. Their counterpart in

					spatial imaging has been widely discussed and demonstrated; however,

					the spectral-domain implementations are few and scarce. We

					experimentally demonstrate a spectroscopic super-resolution method

					aimed at broadband light (tens to hundreds of GHz), and based on the

					spectral-domain analog of image inversion interferometry. In a

					proof-of-principle experiment, we study the paradigmatic problem of

					estimating a small separation between two incoherent spectral features

					of equal brightness, with a small number of photons per coherence

					time. On the grounds of asymptotic estimation theory, more than a

					two-fold improvement over the spectral direct imaging is demonstrated

					in terms of required resources (photons) for a given estimator

					variance. The setup is based on an actively stabilized

					Mach–Zehnder-type interferometer with electro-optic time lenses and

					passive spectral dispersers implementing the inversion. As such, the

					method promises on-chip integration, good scalability, and further

					applications, e.g., for mode sorting.</jats:p>},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mazelanik2023,

title = {Coherent optical two-photon resonance tomographic imaging in three dimensions},

author = {Mateusz Mazelanik and Adam Leszczyński and Tomasz Szawełło and Michał Parniak},

doi = {10.1038/s42005-023-01284-z},

issn = {2399-3650},

year  = {2023},

date = {2023-12-00},

journal = {Commun Phys},

volume = {6},

number = {1},

publisher = {Springer Science and Business Media LLC},

abstract = {AbstractMagnetic resonance imaging is a three-dimensional imaging technique, where a gradient of the magnetic field is used to interrogate spin resonances with spatial resolution. The application of this technique to probe the coherence of atoms with good three-dimensional resolution is a challenging application. We propose and demonstrate an optical method to probe spin resonances via a two-photon Raman transition, reconstructing the 3D-structure of an atomic ensemble’s coherence, which is itself subject to external fields. Our method relies on a single time-and-space resolved heterodyne measurement, allowing the reconstruction of a complex 3D coherence profile. Owing to the optical interface, we reach a tomographic image resolution of 14 × 14 × 36 μm3. The technique allows to probe any transparent medium with a resonance structure and provides a robust diagnostic tool for atom-based quantum information protocols. As such, it is a viable technique for application to magnetometry, electrometry, and imaging of electromagnetic fields.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Han2023,

title = {Microwave electrometry with bichromatic electromagnetically induced transparency in Rydberg atoms},

author = {Mingzhi Han and He Hao and Xiaoyun Song and Zheng Yin and Michal Parniak and Zhengmao Jia and Yandong Peng},

doi = {10.1140/epjqt/s40507-023-00184-z},

issn = {2196-0763},

year  = {2023},

date = {2023-12-00},

journal = {EPJ Quantum Technol.},

volume = {10},

number = {1},

publisher = {Springer Science and Business Media LLC},

abstract = {AbstractA scheme for measuring microwave (MW) electric (E) fields is proposed based on bichromatic electromagnetically induced transparency (EIT) in Rydberg atoms. A bichromatic control field drives the excited state transition, whose absorption shows three EIT windows. When a MW field drives the Rydberg transition, the EIT windows split and six transmission peaks appear. It is interesting to find that the peak-to-peak distance of transmission spectrum is sensitive to the MW field strength, which can be used to measure MW E-field. Simulation results show that the spectral resolution could be increased by about 4 times, and the minimum detectable strength of the MW E-field may be improved by about 3 times compared with the common EIT scheme. After the Doppler averaging, the minimum detectable MW E-field strength is about 5 times larger than that without Doppler effect. Also, we investigate other effects on the sensitivity of the system.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{He2023,

title = {Enhanced coherent microwave-to-optics conversion based on second-order nonlinearity},

author = {Yuan He and Mingzhi Han and Qianzhu Li and Zhengmao Jia and Bing Chen and Leqiu Wang and Michal Parniak and Yandong Peng},

doi = {10.1016/j.optcom.2023.129639},

issn = {0030-4018},

year  = {2023},

date = {2023-10-00},

journal = {Optics Communications},

volume = {545},

publisher = {Elsevier BV},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Niewelt2023,

title = {Experimental Implementation of the Optical Fractional Fourier Transform in the Time-Frequency Domain},

author = {Bartosz Niewelt and Marcin Jastrzębski and Stanisław Kurzyna and Jan Nowosielski and Wojciech Wasilewski and Mateusz Mazelanik and Michał Parniak},

doi = {10.1103/physrevlett.130.240801},

issn = {1079-7114},

year  = {2023},

date = {2023-06-00},

journal = {Phys. Rev. Lett.},

volume = {130},

number = {24},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mazelanik2022,

title = {Optical-domain spectral super-resolution via a quantum-memory-based time-frequency processor},

author = {Mateusz Mazelanik and Adam Leszczyński and Michał Parniak},

doi = {10.1038/s41467-022-28066-5},

issn = {2041-1723},

year  = {2022},

date = {2022-12-00},

urldate = {2022-12-00},

journal = {Nat Commun},

volume = {13},

number = {691},

publisher = {Springer Science and Business Media LLC},

abstract = {<jats:title>Abstract</jats:title><jats:p>Existing super-resolution methods of optical imaging hold a solid place as an application in natural sciences, but many new developments allow for beating the diffraction limit in a more subtle way. One of the recently explored strategies to fully exploit information already present in the field is to perform a quantum-inspired tailored measurements. Here we exploit the full spectral information of the optical field in order to beat the Rayleigh limit in spectroscopy. We employ an optical quantum memory with spin-wave storage and an embedded processing capability to implement a time-inversion interferometer for input light, projecting the optical field in the symmetric-antisymmetric mode basis. Our tailored measurement achieves a resolution of 15 kHz and requires 20 times less photons than a corresponding Rayleigh-limited conventional method. We demonstrate the advantage of our technique over both conventional spectroscopy and heterodyne measurements, showing potential for application in distinguishing ultra-narrowband emitters, optical communication channels, or signals transduced from lower-frequency domains.</jats:p>},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Albarelli2022,

title = {Quantum Asymmetry and Noisy Multimode Interferometry},

author = {Francesco Albarelli and Mateusz Mazelanik and Michał Lipka and Alexander Streltsov and Michał Parniak and Rafał Demkowicz-Dobrzański},

doi = {10.1103/physrevlett.128.240504},

issn = {1079-7114},

year  = {2022},

date = {2022-06-00},

journal = {Phys. Rev. Lett.},

volume = {128},

number = {24},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kurzyna2022,

title = {Variable electro-optic shearing interferometry for ultrafast single-photon-level pulse characterization},

author = {Stanisław Kurzyna and Marcin Jastrzębski and Nicolas Fabre and Wojciech Wasilewski and Michał Lipka and Michał Parniak},

doi = {10.1364/oe.471108},

issn = {1094-4087},

year  = {2022},

date = {2022-00-00},

journal = {Opt. Express},

volume = {30},

number = {22},

publisher = {Optica Publishing Group},

abstract = {Despite the multitude of available methods, the characterization of ultrafast pulses remains a challenging endeavor, especially at the single-photon level. We introduce a pulse characterization scheme that maps the magnitude of its short-time Fourier transform. Contrary to many well-known solutions it does not require nonlinear effects and is therefore suitable for single-photon-level measurements. Our method is based on introducing a series of controlled time and frequency shifts, where the latter is performed via an electro-optic modulator allowing a fully-electronic experimental control. We characterized the full spectral and temporal width of a classical and single-photon-level pulse and successfully tested the applicability of the reconstruction algorithm of the spectral phase and amplitude. The method can be extended by implementing a phase-sensitive measurement and is naturally well-suited to partially-incoherent light.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Borówka2022,

title = {Sensitivity of a Rydberg-atom receiver to frequency and amplitude				modulation of microwaves},

author = {Sebastian Borówka and Uliana Pylypenko and Mateusz Mazelanik and Michał Parniak},

doi = {10.1364/ao.472295},

issn = {2155-3165},

year  = {2022},

date = {2022-00-00},

urldate = {2022-00-00},

journal = {Appl. Opt.},

volume = {61},

number = {29},

publisher = {Optica Publishing Group},

abstract = {<jats:p>Electromagnetically induced transparency in atomic systems involving Rydberg states

					is known to be a sensitive probe of incident microwave (MW) fields, in

					particular those resonant with Rydberg-to-Rydberg transitions. Here we

					propose an intelligible analytical model of a Rydberg atomic

					receiver’s response to amplitude- (AM) and frequency-modulated (FM)

					signals and compare it with experimental results, presenting a setup

					that allows sending signals with either AM or FM and evaluating their

					efficiency with demodulation. Additionally, the setup reveals a

					detection configuration using all circular polarizations for optical

					fields and allowing detection of a circularly polarized MW field,

					propagating colinearly with optical beams. In our measurements, we

					systematically show that several parameters exhibit local optimum

					characteristics and then estimate these optimal parameters and working

					ranges, addressing the need to devise a robust Rydberg MW sensor and

					its operational protocol.</jats:p>},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lipka2021d,

title = {Massively-multiplexed generation of Bell-type entanglement using a quantum memory},

author = {Michał Lipka and Mateusz Mazelanik and Adam Leszczyński and Wojciech Wasilewski and Michał Parniak},

doi = {10.1038/s42005-021-00551-1},

issn = {2399-3650},

year  = {2021},

date = {2021-12-00},

journal = {Commun Phys},

volume = {4},

number = {1},

publisher = {Springer Science and Business Media LLC},

abstract = {AbstractHigh-rate generation of hybrid photon-matter entanglement remains a fundamental building block of quantum network architectures enabling protocols such as quantum secure communication or quantum distributed computing. While a tremendous effort has been made to overcome technological constraints limiting the efficiency and coherence times of current systems, an important complementary approach is to employ parallel and multiplexed architectures. Here we follow this approach experimentally demonstrating the generation of bipartite polarization-entangled photonic states across more than 500 modes, with a programmable delay for the second photon enabled by qubit storage in a wavevector-multiplexed cold-atomic quantum memory. We demonstrate Clauser, Horne, Shimony, Holt inequality violation by over 3 standard deviations, lasting for at least 45 μs storage time for half of the modes. The ability to shape hybrid entanglement between the polarization and wavevector degrees of freedom provides not only multiplexing capabilities but also brings prospects for novel protocols.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lipka2021,

title = {Single-Photon Hologram of a Zero-Area Pulse},

author = {Michał Lipka and Michał Parniak},

doi = {10.1103/physrevlett.127.163601},

issn = {1079-7114},

year  = {2021},

date = {2021-10-00},

journal = {Phys. Rev. Lett.},

volume = {127},

number = {16},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mazelanik2021,

title = {Real-time ghost imaging of Bell-nonlocal entanglement between a photon and a quantum memory},

author = {Mateusz Mazelanik and Adam Leszczyński and Michał Lipka and Wojciech Wasilewski and Michał Parniak},

doi = {10.22331/q-2021-07-01-493},

issn = {2521-327X},

year  = {2021},

date = {2021-07-01},

journal = {Quantum},

volume = {5},

publisher = {Verein zur Forderung des Open Access Publizierens in den Quantenwissenschaften},

abstract = {Certification of nonlocality of quantum mechanics is an important fundamental test that typically requires prolonged data collection and is only revealed in an in-depth analysis. These features are often particularly exposed in hybrid systems, such as interfaces between light and atomic ensembles. Certification of entanglement from images acquired with single-photon camera can mitigate this issue by exploiting multiplexed photon generation. Here we demonstrate this feature in a quantum memory (QM) operating in a real-time feedback mode. Through spatially-multimode spin-wave storage the QM enables operation of the real-time ghost imaging (GI) protocol. By properly preparing the spatial phase of light emitted by the atoms we enable observation of Bell-type nonlocality from a single image acquired in the far field as witnessed by the Bell parameter of S=2.227±0.007>2. Our results are an important step towards fast and efficient utilization of multimode quantum memories both in protocols and in fundamental tests.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lipka2021c,

title = {Entanglement distribution with wavevector-multiplexed quantum memory},

author = {Michał Lipka and Mateusz Mazelanik and Michał Parniak},

doi = {10.1088/1367-2630/abf79a},

issn = {1367-2630},

year  = {2021},

date = {2021-05-01},

journal = {New J. Phys.},

volume = {23},

number = {5},

publisher = {IOP Publishing},

abstract = {Abstract

               Feasible distribution of quantum entanglement over long distances remains a fundamental step towards quantum secure communication and quantum network implementations. Quantum repeater nodes based on quantum memories promise to overcome exponential signal decay inherent to optical implementations of quantum communication. While performance of current quantum memories hinders their practical application, multimode solutions with multiplexing can offer tremendous increase in entanglement distribution rates. We propose to use a wavevector-multiplexed atomic quantum memory (WV-MUX-QM) as a fundamental block of a multiplexed quantum repeater architecture. We show the WV-MUX-QM platform to provide quasi-deterministic entanglement generation over extended distances, mitigating the fundamental issue of optical loss even with currently available quantum memory devices, and exceeding performance of repeaterless solutions as well as other repeater-based protocols such as temporal multiplexing. We establish the entangled-bit (ebit) rate per number of employed nodes as a practical figure of merit reflecting the cost-efficiency of larger inter-node distances.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Thomas2020,

title = {Entanglement between distant macroscopic mechanical and spin systems},

author = {Rodrigo A. Thomas and Michał Parniak and Christoffer Østfeldt and Christoffer B. Møller and Christian Bærentsen and Yeghishe Tsaturyan and Albert Schliesser and Jürgen Appel and Emil Zeuthen and Eugene S. Polzik},

doi = {10.1038/s41567-020-1031-5},

issn = {1745-2481},

year  = {2021},

date = {2021-02-00},

journal = {Nat. Phys.},

volume = {17},

number = {2},

pages = {228--233},

publisher = {Springer Science and Business Media LLC},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Thomas2021,

title = {Calibration of spin-light coupling by coherently induced Faraday rotation},

author = {Rodrigo A. Thomas and Christoffer Østfeldt and Christian Bærentsen and Michał Parniak and Eugene S. Polzik},

doi = {10.1364/oe.425613},

issn = {1094-4087},

year  = {2021},

date = {2021-00-00},

journal = {Opt. Express},

volume = {29},

number = {15},

publisher = {Optica Publishing Group},

abstract = {Calibrating the strength of the light-matter interaction is an important experimental task in quantum information and quantum state engineering protocols. The strength of the off-resonant light-matter interaction in multi-atom spin oscillators can be characterized by the readout rate ΓS. Here we introduce the method named Coherently Induced FAraday Rotation (CIFAR) for determining the readout rate. The method is suited for both continuous and pulsed readout of the spin oscillator, relying only on applying a known polarization modulation to the probe laser beam and detecting a known optical polarization component. Importantly, the method does not require changes to the optical and magnetic fields performing the state preparation and probing. The CIFAR signal is also independent of the probe beam photo-detection quantum efficiency, and allows direct extraction of other parameters of the interaction, such as the tensor coupling ζS, and the damping rate γS. We verify this method in the continuous wave regime, probing a strongly coupled spin oscillator prepared in a warm cesium atomic vapour.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lipka2021b,

title = {Fast imaging of multimode transverse–spectral correlations for twin photons},

author = {Michał Lipka and Michał Parniak},

doi = {10.1364/ol.417658},

issn = {1539-4794},

year  = {2021},

date = {2021-00-00},

journal = {Opt. Lett.},

volume = {46},

number = {13},

publisher = {Optica Publishing Group},

abstract = {Hyperentangled photonic states—exhibiting nonclassical correlations in

					several degrees of freedom—offer improved performance of quantum

					optical communication and computation schemes. Experimentally, a

					hyperentanglement of transverse-wave-vector and spectral modes can be

					obtained in a straightforward way with multimode parametric

					single-photon sources. Nevertheless, experimental characterization of

					such states remains challenging. Not only single-photon detection with

					high spatial resolution—a single-photon camera—is required, but also a

					suitable mode converter to observe the spectral–temporal degree of

					freedom. We experimentally demonstrate a measurement of full

					four-dimensional transverse-wave-vector–spectral correlations between

					pairs of photons produced in noncollinear spontaneous parametric

					downconversion. Utilization of a custom ultrafast single-photon camera

					provides high resolution and a short measurement time.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Parniak2021,

title = {High-frequency broadband laser phase noise cancellation using a delay line},

author = {Michał Parniak and Ivan Galinskiy and Timo Zwettler and Eugene S. Polzik},

doi = {10.1364/oe.415942},

issn = {1094-4087},

year  = {2021},

date = {2021-00-00},

journal = {Opt. Express},

volume = {29},

number = {5},

publisher = {Optica Publishing Group},

abstract = {Laser phase noise remains a limiting factor in many experimental settings, including metrology, time-keeping, as well as quantum optics. Hitherto this issue was addressed at low frequencies ranging from well below 1 Hz to maximally 100 kHz. However, a wide range of experiments, such as, e.g., those involving nanomechanical membrane resonators, are highly sensitive to noise at higher frequencies in the range of 100 kHz to 10 MHz, such as nanomechanical membrane resonators. Here we employ a fiber-loop delay line interferometer optimized to cancel laser phase noise at frequencies around 1.5 MHz. We achieve noise reduction in 300 kHz-wide bands with a peak reduction of more than 10 dB at desired frequencies, reaching phase noise of less than −160 dB(rad2/Hz) with a Ti:Al2O3 laser. These results provide a convenient noise reduction technique to achieve deep ground-state cooling of mechanical motion.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Len2020,

title = {Resolution limits of spatial mode demultiplexing with noisy detection},

author = {Yink Loong Len and Chandan Datta and Michał Parniak and Konrad Banaszek},

doi = {10.1142/s0219749919410156},

issn = {1793-6918},

year  = {2020},

date = {2020-02-00},

journal = {Int. J. Quantum Inform.},

volume = {18},

number = {01},

publisher = {World Scientific Pub Co Pte Lt},

abstract = { We consider the problem of estimating the spatial separation between two mutually incoherent point light sources using the super-resolution imaging technique based on spatial mode demultiplexing (SPADE) with noisy detectors. We show that in the presence of noise, the resolution of the measurement is limited by the signal-to-noise ratio (SNR) and the minimum resolvable spatial separation has a characteristic dependence of [Formula: see text]. Several detection techniques, including direct photon counting, as well as homodyne and heterodyne detection are considered. },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Galinskiy2020,

title = {Phonon counting thermometry of an ultracoherent membrane resonator near its motional ground state},

author = {I. Galinskiy and Y. Tsaturyan and M. Parniak and E. S. Polzik},

doi = {10.1364/optica.390939},

issn = {2334-2536},

year  = {2020},

date = {2020-00-00},

journal = {Optica},

volume = {7},

number = {6},

publisher = {Optica Publishing Group},

abstract = {The generation of non-Gaussian quantum states of macroscopic mechanical

					objects is key to a number of challenges in quantum information

					science, ranging from fundamental tests of decoherence to quantum

					communication and sensing. Heralded generation of single-phonon states

					of mechanical motion is an attractive way toward this goal, as it is,

					in principle, not limited by the object size. Here we demonstrate a

					technique that allows for generation and detection of a quantum state

					of motion by phonon counting measurements near the ground state of a

					1.5 MHz micromechanical oscillator. We detect scattered photons from a

					membrane-in-the-middle optomechanical system using an ultra-narrowband

					optical filter, and perform Raman-ratio thermometry and second-order

					intensity interferometry near the motional ground state (

      

	

	  

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	=

	0.23

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	  p

	  h

	  o

	  n

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    ). With an effective mass in the

					nanogram range, our system lends itself for studies of long-lived

					non-Gaussian motional states with some of the heaviest objects to

					date.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mazelanik2020,

title = {Temporal imaging for ultra-narrowband few-photon states of light},

author = {Mateusz Mazelanik and Adam Leszczyński and Michał Lipka and Michał Parniak and Wojciech Wasilewski},

doi = {10.1364/optica.382891},

issn = {2334-2536},

year  = {2020},

date = {2020-00-00},

journal = {Optica},

volume = {7},

number = {3},

publisher = {Optica Publishing Group},

abstract = {Plenty of quantum information protocols are enabled by manipulation and detection of photonic spectro-temporal degrees of freedom via light–matter interfaces. While present implementations are well suited for high-bandwidth photon sources such as quantum dots, they lack the high resolution required for intrinsically narrowband light–atom interactions. Here, we demonstrate far-field temporal imaging based on ac-Stark spatial spin-wave phase manipulation in a multimode gradient echo memory. We achieve a spectral resolution of 20 kHz with MHz-level bandwidth and an ultralow noise equivalent to 0.023 photons, enabling operation in the single-quantum regime.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mazelanik2019b,

title = {Coherent spin-wave processor of stored optical pulses},

author = {Mateusz Mazelanik and Michał Parniak and Adam Leszczyński and Michał Lipka and Wojciech Wasilewski},

doi = {10.1038/s41534-019-0136-0},

issn = {2056-6387},

year  = {2019},

date = {2019-12-00},

journal = {npj Quantum Inf},

volume = {5},

number = {1},

publisher = {Springer Science and Business Media LLC},

abstract = {AbstractA device being a pinnacle of development of an optical quantum memory should combine the capabilities of storage, inter-communication, and processing of stored information. In particular, the ability to capture a train of optical pulses, interfere them in an arbitrary way and finally, perform on-demand release could realize arbitrary optical computation. Here we demonstrate the operation of a coherent optical memory being able to store optical pulses in the form of collective spin-wave excitations in a two-dimensional wavevector space. During storage, we perform complex beamsplitter operations and demonstrate a variety of protocols implemented at the processing stage, including real-time controlled interference of a pair of spin-wave modes with 95% visibility. The highly multimode structure of the presented memory lends itself to enhancing classical optical telecommunication, as well as parallel processing of optical qubits at the single-photon level.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mazelanik2019,

title = {Superradiant parametric conversion of spin waves},

author = {Mateusz Mazelanik and Adam Leszczyński and Michał Lipka and Wojciech Wasilewski and Michał Parniak},

doi = {10.1103/physreva.100.053850},

issn = {2469-9934},

year  = {2019},

date = {2019-11-00},

journal = {Phys. Rev. A},

volume = {100},

number = {5},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lipka2019,

title = {Spatial Spin-Wave Modulator for Quantum-Memory-Assisted Adaptive Measurements},

author = {Michał Lipka and Adam Leszczyński and Mateusz Mazelanik and Michał Parniak and Wojciech Wasilewski},

doi = {10.1103/physrevapplied.11.034049},

issn = {2331-7019},

year  = {2019},

date = {2019-03-00},

journal = {Phys. Rev. Applied},

volume = {11},

number = {3},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Parniak2019,

title = {Quantum Optics of Spin Waves through ac Stark Modulation},

author = {Michał Parniak and Mateusz Mazelanik and Adam Leszczyński and Michał Lipka and Michał Dąbrowski and Wojciech Wasilewski},

doi = {10.1103/physrevlett.122.063604},

issn = {1079-7114},

year  = {2019},

date = {2019-02-00},

journal = {Phys. Rev. Lett.},

volume = {122},

number = {6},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Parniak2018,

title = {Beating the Rayleigh Limit Using Two-Photon Interference},

author = {Michał Parniak and Sebastian Borówka and Kajetan Boroszko and Wojciech Wasilewski and Konrad Banaszek and Rafał Demkowicz-Dobrzański},

doi = {10.1103/physrevlett.121.250503},

issn = {1079-7114},

year  = {2018},

date = {2018-12-00},

journal = {Phys. Rev. Lett.},

volume = {121},

number = {25},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dąbrowski2018,

title = {Certification of high-dimensional entanglement and Einstein-Podolsky-Rosen steering with cold atomic quantum memory},

author = {Michał Dąbrowski and Mateusz Mazelanik and Michał Parniak and Adam Leszczyński and Michał Lipka and Wojciech Wasilewski},

doi = {10.1103/physreva.98.042126},

issn = {2469-9934},

year  = {2018},

date = {2018-10-00},

journal = {Phys. Rev. A},

volume = {98},

number = {4},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lipka2018,

title = {Microchannel plate cross-talk mitigation for spatial autocorrelation measurements},

author = {Michał Lipka and Michał Parniak and Wojciech Wasilewski},

doi = {10.1063/1.5033559},

issn = {1077-3118},

year  = {2018},

date = {2018-05-21},

urldate = {2018-05-21},

journal = {Appl. Phys. Lett.},

volume = {112},

number = {21},

publisher = {AIP Publishing},

abstract = {<jats:p>Microchannel plates (MCP) are the basis for many spatially resolved single-particle detectors such as ICCD or I-sCMOS cameras employing image intensifiers (II), MCPs with delay-line anodes for the detection of cold gas particles or Cherenkov radiation detectors. However, the spatial characterization provided by an MCP is severely limited by cross-talk between its microchannels, rendering MCP and II ill-suited for autocorrelation measurements. Here, we present a cross-talk subtraction method experimentally exemplified for an I-sCMOS based measurement of pseudo-thermal light second-order intensity autocorrelation function at the single-photon level. The method merely requires a dark counts measurement for calibration. A reference cross-correlation measurement certifies the cross-talk subtraction. While remaining universal for MCP applications, the presented cross-talk subtraction, in particular, simplifies quantum optical setups. With the possibility of autocorrelation measurements, the signal needs no longer to be divided into two camera regions for a cross-correlation measurement, reducing the experimental setup complexity and increasing at least twofold the simultaneously employable camera sensor region.</jats:p>},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Parniak2017,

title = {Wavevector multiplexed atomic quantum memory via spatially-resolved single-photon detection},

author = {Michał Parniak and Michał Dąbrowski and Mateusz Mazelanik and Adam Leszczyński and Michał Lipka and Wojciech Wasilewski},

doi = {10.1038/s41467-017-02366-7},

issn = {2041-1723},

year  = {2017},

date = {2017-12-00},

urldate = {2017-12-00},

journal = {Nat Commun},

volume = {8},

number = {2140},

publisher = {Springer Science and Business Media LLC},

abstract = {<jats:title>Abstract</jats:title><jats:p>Parallelized quantum information processing requires tailored quantum memories to simultaneously handle multiple photons. The spatial degree of freedom is a promising candidate to facilitate such photonic multiplexing. Using a single-photon resolving camera, we demonstrate a wavevector multiplexed quantum memory based on a cold atomic ensemble. Observation of nonclassical correlations between Raman scattered photons is confirmed by an average value of the second-order correlation function <jats:inline-formula><jats:alternatives><jats:tex-math>$$g_{{mathrm{S,AS}}}^{{mathrm{(2)}}} = 72 pm 5$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">

                      <mml:msubsup>

                        <mml:mrow>

                          <mml:mi>g</mml:mi>

                        </mml:mrow>

                        <mml:mrow>

                          <mml:mi>S,AS</mml:mi>

                        </mml:mrow>

                        <mml:mrow>

                          <mml:mi>(2)</mml:mi>

                        </mml:mrow>

                      </mml:msubsup>

                      <mml:mo>=</mml:mo>

                      <mml:mn>72</mml:mn>

                      <mml:mo>±</mml:mo>

                      <mml:mn>5</mml:mn>

                    </mml:math></jats:alternatives></jats:inline-formula> in 665 separated modes simultaneously. The proposed protocol utilizing the multimode memory along with the camera will facilitate generation of multi-photon states, which are a necessity in quantum-enhanced sensing technologies and as an input to photonic quantum circuits.</jats:p>},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lipka2017,

title = {Optical frequency locked loop for long-term stabilization of broad-line DFB laser frequency difference},

author = {Michał Lipka and Michał Parniak and Wojciech Wasilewski},

doi = {10.1007/s00340-017-6808-6},

issn = {1432-0649},

year  = {2017},

date = {2017-09-00},

journal = {Appl. Phys. B},

volume = {123},

number = {9},

publisher = {Springer Science and Business Media LLC},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Leszczyński2017,

title = {Phase matching alters spatial multiphoton processes in dense atomic ensembles},

author = {Adam Leszczyński and Michał Parniak and Wojciech Wasilewski},

doi = {10.1364/oe.25.000284},

issn = {1094-4087},

year  = {2017},

date = {2017-00-00},

journal = {Opt. Express},

volume = {25},

number = {1},

publisher = {The Optical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dąbrowski2017,

title = {Einstein–Podolsky–Rosen paradox in a hybrid bipartite system},

author = {Michał Dąbrowski and Michał Parniak and Wojciech Wasilewski},

doi = {10.1364/optica.4.000272},

issn = {2334-2536},

year  = {2017},

date = {2017-00-00},

urldate = {2017-00-00},

journal = {Optica},

volume = {4},

number = {2},

pages = {272-275},

publisher = {The Optical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Parniak2015,

title = {Multimode Raman light-atom interface in warm atomic ensemble as multiple three-mode quantum operations},

author = {Michał Parniak and Daniel Pęcak and Wojciech Wasilewski},

doi = {10.1080/09500340.2015.1125538},

issn = {1362-3044},

year  = {2016},

date = {2016-11-12},

journal = {Journal of Modern Optics},

volume = {63},

number = {20},

pages = {2039--2047},

publisher = {Informa UK Limited},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Parniak2016,

title = {Coupling of four-wave mixing and Raman scattering by ground-state atomic coherence},

author = {Michał Parniak and Adam Leszczyński and Wojciech Wasilewski},

doi = {10.1103/physreva.93.053821},

issn = {2469-9934},

year  = {2016},

date = {2016-05-00},

journal = {Phys. Rev. A},

volume = {93},

number = {5},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Parniak2016b,

title = {Magneto-optical polarization rotation in a ladder-type atomic system for tunable offset locking},

author = {Michał Parniak and Adam Leszczyński and Wojciech Wasilewski},

doi = {10.1063/1.4947104},

issn = {1077-3118},

year  = {2016},

date = {2016-04-18},

urldate = {2016-04-18},

journal = {Appl. Phys. Lett.},

volume = {108},

number = {16},

publisher = {AIP Publishing},

abstract = {<jats:p>We demonstrate an easily tunable locking scheme for stabilizing frequency-sum of two lasers on a two-photon ladder transition based on polarization rotation in warm rubidium vapors induced by magnetic field and circularly polarized drive field. Unprecedented tunability of the two-photon offset frequency is due to strong splitting and shifting of magnetic states in external field. In our experimental setup, we achieve two-photon detuning of up to 700 MHz.</jats:p>},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Parniak2015b,

title = {Interference and nonlinear properties of four-wave-mixing resonances in thermal vapor: Analytical results and experimental verification},

author = {Michał Parniak and Wojciech Wasilewski},

doi = {10.1103/physreva.91.023418},

issn = {1094-1622},

year  = {2015},

date = {2015-02-00},

urldate = {2015-02-00},

journal = {Phys. Rev. A},

volume = {91},

number = {023418},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dąbrowski2014,

title = {Spontaneuos and Parametric Processes in Warm Rubidium Vapours},

author = {M. Dąbrowski and M. Parniak and D. Pęcak and R. Chrapkiewicz and W. Wasilewski},

doi = {10.2478/lpts-2014-0028},

issn = {0868-8257},

year  = {2014},

date = {2014-12-15},

volume = {51},

number = {5},

pages = {21--34},

publisher = {Walter de Gruyter GmbH},

abstract = {Abstract

               Warm rubidium vapours are known to be a versatile medium for a variety of experiments in atomic physics and quantum optics. Here we present experimental results on producing the frequency converted light for quantum applications based on spontaneous and stimulated processes in rubidium vapours. In particular, we study the efficiency of spontaneously initiated stimulated Raman scattering in the Λ-level configuration and conditions of generating the coherent blue light assisted by multi-photon transitions in the diamond-level configuration. Our results will be helpful in search for new types of interfaces between light and atomic quantum memories.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Parniak2013,

title = {Direct observation of atomic diffusion in warm rubidium ensembles},

author = {Michał Parniak and Wojciech Wasilewski},

doi = {10.1007/s00340-013-5712-y},

issn = {1432-0649},

year  = {2014},

date = {2014-08-00},

journal = {Appl. Phys. B},

volume = {116},

number = {2},

pages = {415--421},

publisher = {Springer Science and Business Media LLC},

keywords = {},

pubstate = {published},

tppubtype = {article}

}