Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of Experimental and Theoretical Physics Letters

Generation of Optical—Terahertz Biphotons and Detection of Their Terahertz Component under Frequency-Nondegenerate Parametric Down-Conversion

Vitaliy Sultanov, Kirill A. Kuznetsov, A.A. Leontyev, G. Kh. Kitaeva

Published Sep 1, 2020• 9 citations
Publisher

Abstract

The conditions for the generation and detection of quantum-correlated pairs of optical and terahertz photons in the process of strongly frequency-nondegenerate parametric down-conversion of light are investigated. An approach based on increasing the frequency of the optical pump is proposed, whereby the power of a weak flux of terahertz idler photons can be measured for a wide range of parametric gain coefficients, down to the onset of the spontaneous down-conversion regime, using the same terahertz detector with a limited dynamic range. It is shown experimentally that the doubling of the frequency of pulsed laser pump leads to a 5-fold reduction in the lowest value of parametric gain that is still sufficient for detecting terahertz idler photons with a cooled hot-electron bolometer.

DOI
10.1134/s0021364020170099

Related papers

Direct detection of the idler THz radiation generated by spontaneous parametric down-conversion

G. Kh. Kitaeva, Vladimir V. Kornienko, Kirill A. Kuznetsov +3 more

We study parametric down-conversion (PDC) of optical laser radiation in the strongly frequency non-degenerate regime which is promising for the generation of quantum-correlated pairs of extremely different spectral ranges, the optical and the terahertz (THz) ones. The possibility to detect tenuous THz-frequency photon fluxes generated under low-gain spontaneous PDC is demonstrated using a hot electron bolometer. Then experimental dependences of the THz radiation power on the detection angle and on the pump intensity are analyzed.

Optics Letters•Feb 21, 2019•21 citations

Generation and detection of optical-terahertz biphotons via spontaneous parametric downconversion

Kirill A. Kuznetsov, Vladimir V. Kornienko, Yu. B. Vakhtomin +3 more

We study spontaneous parametric downconversion (SPDC) in the strongly non-degenerate regime when the idler wave hits the terahertz range. By using the hot-electron bolometer, for the first time the SPDC-generated idler-wave photons were directly detected in the terahertz frequency range. Spectrum of corresponding signal photons was measured using standard technique by the CCD camera. Possible applications of correlated optical-terahertz biphotons are discussed.

International Conference Laser Optics (ICLO)•Jun 1, 2018•0 citations

Preparation of the Quantum Correlated Optical-Terahertz Biphotons

Kirill A. Kuznetsov, A.A. Leontyev, T. I. Novikova +4 more

We study the conditions necessary for generating non-classical optical-terahertz biphotons by means of spontaneous parametric down-conversion. Using a hot electron bolometer we demonstrate detection of the THz-frequency idler waves generated under parametric up- and down-conversion with a record low gain. Complete disappearance of the classical contribution has been observed at low temperatures. A second-order biphoton correlation function is analyzed.

International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)•Sep 1, 2019•1 citation

Generation of Quantum Correlated Optical - Terahertz Photon Pairs and Calibration of Nonlinear-Optical Detectors via Parametric Down-Conversion

Vladimir V. Kornienko, Kirill A. Kuznetsov, A.A. Leontyev +2 more

Quantum effect of parametric down-conversion is studied in a strongly frequency non-degenerate regime, when pairs of correlated optical and terahertz photons are generated along with parametric amplification and frequency conversion of thermal fluctuations and external radiation at terahertz frequencies. The terahertz photon fluxes emitted due to parametric down-conversion are registered. Direct incoherent nonlinear-optical detection is demonstrated for continuous wave sources at 0.2-0.4 THz.

International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)•Sep 1, 2018•0 citations

Generation of optical signal and terahertz idler photons by spontaneous parametric down-conversion

G. Kh. Kitaeva, Vladimir V. Kornienko, A.A. Leontyev +1 more

Frequency-angular characteristics of signal and idler photons generated under spontaneous parametric down-conversion are studied in a strongly frequency nondegenerate regime, without paraxial approximation, accounting for possible inherent absorption of idler waves in a nonlinear crystal, classical thermal field fluctuations, and the multimode character of parametric interaction induced by transverse spatial limitation of the pump beam. Spatial limitation is shown to lead to a huge increase in angular divergence of the idler photons generated at terahertz frequencies. General expressions are obtained for the frequency-angular sensitivity function of the nonlinear-optical terahertz wave detector and for power densities of the signal and idler photon fluxes. The absorption-induced difference in the parametric conversion coefficients for the noise and externally incident radiation of the idler frequency is shown to be described by approximately the same loss factor for all active spatial idler modes. Two different parametric contributions of the internal thermal noise to the number of output idler photons were revealed with different dependence on the idler-wave absorption. Expressions for the loss factors, which describe absorption-induced effects in signal and idler channels, are obtained and shown to be turning into one another by changing the sign of the absorption coefficient. Relative contribution of thermal and quantum field fluctuations into the intrinsic radiation of a nonlinear crystal at signal and idler frequencies is analyzed accounting for the crystal absorption properties.

Physical Review A•Dec 27, 2018•38 citations

Generation of optical-terahertz biphoton pairs via spontaneous parametric down-conversion

Vladimir V. Kornienko, Semyon Germanskiy, G. Kh. Kitaeva +1 more

We examine the features of parametric down-conversion for generating non-classical optical-terahertz biphoton fields. The calculations were performed for a second-order correlation function and noise reduction factor (NRF), which were selected as measures of non-classicality of the field states. NRF measurement schemes were found to be less advantageous. Overall system temperature at which non-classical effects are still observable has been estimated as about 10 K. The priority of the main complicating factors for the quantum-optical measurements in the terahertz range has been determined. Thus, the most important parameter is the temperature of the system, after that come the absorption losses at terahertz frequencies, and the parametric conversion efficiency has the lowest impact. Increasing the pump radiation power has been found to be inefficient for "noise" suppression in this case. The calculations performed were based on lithium niobate dispersion properties due to its outstanding nonlinear optical properties and because it is frequently used for optical-to-terahertz frequency conversion.

International Journal of Quantum Information•Nov 1, 2014•10 citations
The conditions for the generation and detection of quantum-correlated pairs of optical and terahertz photons in the process of strongly frequency-nondegenerate parametric down-conversion of light are investigated. An approach based on increasing the frequency of the optical pump is proposed, whereby the power of a weak flux of terahertz idler photons can be measured for a wide range of parametric gain coefficients, down to the onset of the spontaneous down-conversion regime, using the same terahertz detector with a limited dynamic range. It is shown experimentally that the doubling of the frequency of pulsed laser pump leads to a 5-fold reduction in the lowest value of parametric gain that is still sufficient for detecting terahertz idler photons with a cooled hot-electron bolometer.
We study parametric down-conversion (PDC) of optical laser radiation in the strongly frequency non-degenerate regime which is promising for the generation of quantum-correlated pairs of extremely different spectral ranges, the optical and the terahertz (THz) ones. The possibility to detect tenuous THz-frequency photon fluxes generated under low-gain spontaneous PDC is demonstrated using a hot electron bolometer. Then experimental dependences of the THz radiation power on the detection angle and on the pump intensity are analyzed.
Frequency-angular characteristics of signal and idler photons generated under spontaneous parametric down-conversion are studied in a strongly frequency nondegenerate regime, without paraxial approximation, accounting for possible inherent absorption of idler waves in a nonlinear crystal, classical thermal field fluctuations, and the multimode character of parametric interaction induced by transverse spatial limitation of the pump beam. Spatial limitation is shown to lead to a huge increase in angular divergence of the idler photons generated at terahertz frequencies. General expressions are obtained for the frequency-angular sensitivity function of the nonlinear-optical terahertz wave detector and for power densities of the signal and idler photon fluxes. The absorption-induced difference in the parametric conversion coefficients for the noise and externally incident radiation of the idler frequency is shown to be described by approximately the same loss factor for all active spatial idler modes. Two different parametric contributions of the internal thermal noise to the number of output idler photons were revealed with different dependence on the idler-wave absorption. Expressions for the loss factors, which describe absorption-induced effects in signal and idler channels, are obtained and shown to be turning into one another by changing the sign of the absorption coefficient. Relative contribution of thermal and quantum field fluctuations into the intrinsic radiation of a nonlinear crystal at signal and idler frequencies is analyzed accounting for the crystal absorption properties.
We examine the features of parametric down-conversion for generating non-classical optical-terahertz biphoton fields. The calculations were performed for a second-order correlation function and noise reduction factor (NRF), which were selected as measures of non-classicality of the field states. NRF measurement schemes were found to be less advantageous. Overall system temperature at which non-classical effects are still observable has been estimated as about 10 K. The priority of the main complicating factors for the quantum-optical measurements in the terahertz range has been determined. Thus, the most important parameter is the temperature of the system, after that come the absorption losses at terahertz frequencies, and the parametric conversion efficiency has the lowest impact. Increasing the pump radiation power has been found to be inefficient for "noise" suppression in this case. The calculations performed were based on lithium niobate dispersion properties due to its outstanding nonlinear optical properties and because it is frequently used for optical-to-terahertz frequency conversion.