Publications

@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{Lipka2024b,

title = {Multiparameter quantum sensing and magnetic communication with a hybrid dc and rf optically pumped magnetometer},

author = {Michał Lipka and Aleksandra Sierant and Charikleia Troullinou and Morgan W. Mitchell},

doi = {10.1103/physrevapplied.21.034054},

issn = {2331-7019},

year  = {2024},

date = {2024-03-00},

urldate = {2024-03-00},

journal = {Phys. Rev. Applied},

volume = {21},

number = {034054},

publisher = {American Physical Society (APS)},

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{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{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{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}

}