arXiv subjects

Mikhail I. Kolobov

Publications and source records attributed to Mikhail I. Kolobov.

16 recordsLinked to original sources

arXiv2025

Low-coherence interferometry with undetected mid-infrared photons in the high-gain regime

We develop a high-parametric-gain SU(1,1) interferometer based on an aperiodically poled Potassium Titanyl Phosphate (apKTP) crystal, enabling frequency-domain low-coherence interferometry with undetected mid-infrared photons. The system achieves a signal-to-noise ratio as high as 40 dB and axial resolution of 30 $μ$m, with a 3 $μ$m-centered idler beam. By increasing the poling-period range, we also improve the axial resolution to 17 $μ$m, demonstrating a straightforward route to enhance the performance by working on the crystal design

physics.optics↗

arXiv2025

Interferometric sorting of temporal Hermite-Gauss modes via temporal Gouy phase

We propose a device consisting of $m$ Mach-Zehnder interferometers and realizing sorting of first $2^m$ temporal Hermite-Gauss modes of light passing though it by adjusting the accumulated temporal Gouy phase acquired by every mode. This mode-order-dependent phase shift is achieved by a fractional Fourier transform realized by a time lens in one of interferometer's arms. We consider application of such a sorter with just two interferometers to sorting the Schmidt modes of a photon pair generated in spontaneous parametric downconversion and find the theoretical lower bond on the cross-talk probability of 5.5%.

quant-ph↗

arXiv2024

Few-mode squeezing in type-I parametric downconversion by complete group velocity matching

Frequency-degenerate pulsed type-I parametric downconversion is a widely used source of squeezed light for numerous quantum optical applications. However, this source is typically spectrally multimode and the generated squeezing is distributed between many spectral modes with a limited degree of squeezing per mode. We show that in a nonlinear crystal, where the condition of complete group velocity matching (GVM) for the pump and the signal is satisfied, the number of generated modes may be as low as two or three modes. We illustrate the general theory with the example of the MgO-doped lithium niobate crystal pumped at 775 nm and generating squeezed light at 1.55 $μ$m. Our model includes the derivation of the degree of squeezing from the properties of the pump and the crystal and shows that 12 dB of squeezing can be obtained in a periodically poled crystal of length 80 mm.

quant-ph↗

arXiv2024

Fourier-transform infrared spectroscopy with undetected photons from high-gain spontaneous parametric down-conversion

Fourier-transform infrared spectroscopy (FTIR) is an indispensable analytical method that allows label-free identification of substances via fundamental molecular vibrations. However, the sensitivity of FTIR is often limited by the low efficiency of mid-infrared (MIR) photodetectors. SU(1,1) interferometry has previously enabled FTIR with undetected MIR photons via spontaneous parametric down-conversion in the low-parametric-gain regime, where the number of photons per mode is much less than one and sensitive photodetectors are needed. In this work, we develop a high-parametric-gain SU(1,1) interferometer for MIR-range FTIR with undetected photons. Using our new method, we demonstrate three major advantages: a high photon number at the interferometer output, a considerably lower photon number at the sample, and improved interference contrast. In addition, we analyze different methods to broaden the spectral range of the interferometer by aperiodic poling and temperature gradient in the gain medium. Exploiting the broadband SU(1,1) interferometer, we measure and evaluate the MIR absorption spectra of polymers in the 3-μm region.

physics.optics↗

arXiv2023

Erecting time telescope for photonic quantum networks

A time lens allows one to stretch or compress optical waveforms in time, similar to the conventional lens in space. However, a single-time-lens imaging system always imparts a residual temporal chirp on the image, which may be detrimental for quantum networks, where the temporal image interacts with other fields. We show that a two-time-lens imaging system satisfying the telescopic condition, a time telescope, is necessary and sufficient for creating a chirpless image. We develop a general theory of a time telescope, find the conditions for loss minimization, and show how an erecting time telescope creating a real image of a temporal object can be constructed. We consider several applications of such a telescope to making indistinguishable the photons generated by spontaneous parametric downconversion or single emitters such as quantum dots.

quant-ph↗

arXiv2023

Making entangled photons indistinguishable by a time lens

We propose an application of quantum temporal imaging to restoring the indistinguishability of the signal and the idler photons produced in type-II spontaneous parametric down-conversion with a pulsed broadband pump. It is known that in this case, the signal and the idler photons have different spectral and temporal properties. This effect deteriorates their indistinguishability and the visibility of the Hong-Ou-Mandel interference, respectively. We demonstrate that inserting a time lens in one arm of the interferometer and choosing properly its magnification factor restores perfect indistinguishability of the signal and the idler photons and provides 100\% visibility of the Hong-Ou-Mandel interference in the limit of high focal group delay dispersion of the time lens.

quant-ph↗

arXiv2018

Quantum effects of operator time ordering in the nonlinear Jaynes-Cummings model

Recently, in [Phys. Rev. A 97, 043806 (2018)], the detuned and nonlinear Jaynes-Cummings model describing the quantized motion of a trapped ion was introduced and its corresponding dynamics was solved via considering the driving laser in a quantized manner. In this work we reconsider this model and show that it can likewise be solved with a classical driving laser field. Using the exact solution we investigate the quantum time-ordering effects of the system with respect to nonclassicality of the motional states of the ion. Furthermore, we use the Magnus expansion to analyze the impact of certain orders of the time ordering and derive and exact radius of convergence beyond the established and only sufficient criterion. Finally, the differences of the solution derived here and the previously found one using a quantized pump, are discussed.

quant-ph↗

arXiv2018

Measuring nonclassicality of bosonic field quantum states via operator ordering sensitivity

We introduce a new distance-based measure for the nonclassicality of the states of a bosonic field, which outperforms the existing such measures in several ways. We define for that purpose the operator ordering sensitivity of the state which evaluates the sensitivity to operator ordering of the Renyi entropy of its quasi-probabilities and which measures the oscillations in its Wigner function. Through a sharp control on the operator ordering sensitivity of classical states we obtain a precise geometric image of their location in the density matrix space allowing us to introduce a distance-based measure of nonclassicality. We analyse the link between this nonclassicality measure and a recently introduced quantum macroscopicity measure, showing how the two notions are distinct.

quant-ph↗

arXiv2017

Broadband bright twin beams and their up-conversion

We report on the observation of broadband (40 THz) bright twin beams through high-gain parametric down-conversion in an aperiodically poled lithium niobate crystal. The output photon number is shown to scale exponentially with the pump power and not with the pump amplitude, as in homogeneous crystals. Photon-number correlations and the number of frequency/temporal modes are assessed by spectral covariance measurements. By using sum-frequency generation on the surface of a non-phasematched crystal, we measure a cross-correlation peak with the temporal width 90 fs.

quant-ph↗

arXiv2017

Controlling induced coherence for quantum imaging

Induced coherence in parametric down-conversion between two coherently pumped nonlinear crystals that share a common idler mode can be used as an imaging technique. Based on the interference between the two signal modes of the crystals, an image can be reconstructed. By obtaining an expression for the interference pattern that is valid in both the low- and the high-gain regimes of parametric down-conversion, we show how the coherence of the light emitted by the two crystals can be controlled. With our comprehensive analysis we provide deeper insight into recent discussions about the application of induced coherence to imaging in different regimes. Moreover, we propose a scheme for optimizing the visibility of the interference pattern so that it directly corresponds to the degree of coherence of the light generated in the two crystals. We find that this scheme leads in the high-gain regime to a visibility arbitrarily close to unity.

quant-ph↗

arXiv2013

Analytical results from the quantum theory of a single-emitter nanolaser. II

Using two equivalent approaches, Heisenberg-Langevin and density operator, we investigate the properties of nanolaser: an incoherently pumped single two-level system interacting with a single-cavity mode of finite finesse. We show that in the case of good-cavity regime the Heisenberg-Langevin approach provides the analytical results for linewidth, amplitude fluctuation spectrum, and intracavity Mandel Q-parameter. In the bad-cavity regime we estimate the frequency at which the peak of relaxation oscillations appears. With the help of the master equation for density operator written in terms of coherent states we obtain approximated expression for Glauber-Sudarshan P function. This solution can be used in the case of good-cavity regime and allows us to investigate in more detail the thresholdless behaviour of the nanolaser. All two approaches are in a very good agreement with each other and numerical simulations.

physics.optics↗

arXiv2009

Mechanisms of rogue wave formation

Freak waves, or rogue waves, are one of the fascinating manifestations of the strength of nature. These devastating walls of water appear from nowhere, are short-lived and extremely rare. Despite the large amount of research activities on this subject, neither the minimum ingredients required for their generation nor the mechanisms explaining their formation have been given. Today, it is possible to reproduce such kind of waves in optical fibre systems. In this context, we demonstrate theoretically and numerically that convective instability is the basic ingredient for the formation of rogue waves. This explains why rogues waves are extremely sensitive to noisy environments.

physics.optics↗

arXiv2006

Quantum teleportation of optical images with frequency conversion

We describe a new version of continuous variables quantum holographic teleportation of optical images. Unlike the previously proposed scheme, it is based on the continuous variables quantum entanglement between the light fields of different frequencies and allows for the wavelength conversion between the original and the teleported images. The frequency tunable holographic teleportation protocol can be used as a part of light-matter interface in parallel quantum information processing and parallel quantum memory

quant-ph↗

arXiv2004

Quantum limits of super-resolution in reconstruction of optical objects

We investigate analytically and numerically the role of quantum fluctuations in reconstruction of optical objects from diffraction-limited images. Taking as example of an input object two closely spaced Gaussian peaks we demonstrate that one can improve the resolution in the reconstructed object over the classical Rayleigh limit. We show that the ultimate quantum limit of resolution in such reconstruction procedure is determined not by diffraction but by the signal-to-noise ratio in the input object. We formulate a quantitative measure of super-resolution in terms of the optical point-spread function of the system.

quant-ph↗

arXiv2004

Squeezed-light source for the superresolving microscopy

We propose a source of multimode squeezed light that can be used for the superresolving microscopy beyond the standard quantum limit. This source is an optical parametric amplifier with a properly chosen diaphragm on its output and a Fourier lens. We demonstrate that such an arrangement produces squeezed prolate spheroidal waves which are the eigen modes of the optical imaging scheme used in microscopy. The degree of squeezing and the number of spatial modes in illuminating light, necessary for the effective object field reconstruction, are evaluated

quant-ph↗

arXiv2003

Quantum fluctuations in superresolving microscopy with squeezed light

We numerically investigate the role of quantum fluctuations in superresolution of optical objects. First, we confirm that when quantum fluctuations are not taken into account, one can easily improve the resolution by one order of magnitude beyond the diffraction limit. Then we investigate the standard quantum limit of superresolution which is achieved for illumination of an object by a light wave in a coherent state. We demonstrate that this limit can be beyond the diffraction limit. Finally, we show that further improvement of superresolution beyond the standard quantum limit is possible using the object illumination by a multimode squeezed light.

quant-ph↗