Towards Measuring Terahertz Photon Statistics by a Superconducting Bolometer

Abstract

Statistical distributions of the analog readings of an antenna-coupled THz superconducting bolometer were measured and analyzed under a special type of irradiation by low-energy fluxes of THz photons with Poisson photon statistics and controllable mean photon numbers. The photons were generated via low-gain parametric down-conversion in pulse-pumped Mg:LiNbO3 crystal placed to a cooled cryostat together with the bolometer NbN film. Results of theoretical approximation of experimental histograms reveal the discrete nature of THz detection by superconducting bolometers and open a way for studying their quantum characteristics. It is shown that bolometer readings per pulse consist of discrete counts (“single charges”), with the mean number linearly dependent on the number of input photons. Contributions of single counts to a total analog reading are statistically distributed according to the normal law, with average values slightly depending on the number of counts in each reading. A general formula is proposed to describe the relationship between continuous statistical distribution of the bolometer readings and discrete quantum statistics of the incident photons.

Charge Dynamics Electron Microscopy: Nanoscale Imaging of Femtosecond Plasma Dynamics

“…The intense nanoscale THz fields produced by the diagnosed plasma hold strong potential for use in the spatial, angular, and spectral compression of e-beams, enabling finer spatiotemporal control with respect to traditional THz-based approaches. , CDEM could thus be applied to manipulate the wave function of free electrons in ways that existing techniques such as PINEM cannot. In addition, the photon statistics of the THz field associated with the out-of-equilibrium plasma remains as a fundamental question that cannot be addressed with conventional quantum-optics techniques because of the limited speed and sensitivity of available THz photodetectors. − CDEM is thus offering a viable approach to characterize the statistics of near-field photons at low frequencies.…”

“…In addition, the photon statistics of the THz field associated with the out-of-equilibrium plasma remains as a fundamental question 38 that cannot be addressed with conventional quantum-optics techniques because of the limited speed and sensitivity of available THz photodetectors. 39 − 41 CDEM is thus offering a viable approach to characterize the statistics of near-field photons at low frequencies.…”

Charge dynamics electron microscopy: nanoscale imaging of femtosecond plasma dynamics

“…CDEM could thus be applied to manipulate the wave function of free-electrons in ways that existing techniques such as PINEM cannot. In addition, the photon statistics of the THz field associated with the out-of-equilibrium plasma remains as a fundamental question [39] that cannot be addressed with conventional quantum-optics techniques because of the limited speed and sensitivity of available THz photodetectors [40][41][42]. CDEM is thus offering a viable approach to characterize the statistics of near-field photons at low frequencies.…”

Terahertz communication: detection and signal processing

“…Marginal fluctuations in temperature, instigated by incident radiation, can subsequently propel the superconductor beyond its critical temperature, eliciting significant resistance alterations. This characteristic culminates in a bolometer that exhibits superior sensitivity compared to those fabricated from conventional materials [42,43]. As the original edition of hot electron bolometer (HEB) device, one attractive sandwich-like structural design-superconductor-insulator-superconductor (SIS) has been widely used in superconductor-based detectors.…”