The operation of our atmospheric quantum cryptography system using the BB84 protocol and polarization coding is experimentally studied. The distribution rate of the sifted quantum key and the quantum bit error rate in the key remained constant for 1 hour and were 7558± 83 bit s ^-1 and 5.1± 0.84% , respectively, at the distance of 20 m between the transmitter and receiver. The minimum possible transmittance of a quantum channel, ensuring the security of a quantum key, is calculated for the given parameters of the system

Экспериментально исследована работа созданной нами атмосферной установки для генерации квантового ключа, использующей протокол квантовой криптографии BB84 и поляризационное кодирование. Скорость генерации «просеянного» квантового ключа и уровень ошибочных битов в нём оставались постоянными в течение 1 ч и равнялись 7558 ± 83 бит/с и 5 , 1 ± 0 , 84 % соответственно при расстоянии между передатчиком и приёмником 20 м. Для приведённых параметров установки рассчитан минимально возможный коэффициент пропускания квантового канала, обеспечивающий секретность квантового ключа. The operation of our atmospheric quantum cryptography setup using the BB84 protocol and polarization coding has been investigated experimentally. The "sifted" quantum key distribution rate and the quantum bit error rate in the key remain constant for 1 hour and are equal to 7558±83 bit/s and 5.1±0.84%, respectively, at a distance of 20 m between the transmitter and receiver. The minimum possible transmittance of a quantum channel is calculated for these parameters of our setup.

Results on the creation and properties of transistor-type MIS structures (MIST) with an Al2O3 thin-film gate dielectric based on PbSnTe:In films obtained by molecular beam epitaxy are presented. The source-drain current-voltage characteristics (CVC) and gate characteristics of the MIST at Т = 4.2 К have been investigated. It is shown that in MIST based on PbSnTe:In films with n ~ 1017 cm-3 the modulation of the channel current reaches 7 – 8 % in the range of gate voltages – 10 V < Ugate < + 10 V. The features of the source-drain CVC and the gate characteristics for a pulsed and sawtooth variation of Ugate are considered.

Разработан и изготовлен детектор одиночных фотонов на базе лавинных фотодиодов (ОЛФД) InP / InGaAs / InP, работающих на длине волны 1550 нм. Приведено описание конструкции, способа получения гетероструктуры и изготовления чипа ОЛФД. Представлены предварительные результаты измерений параметров изготовленных ОЛФД.

Для практической реализации квантовых коммуникаций требуются высокоэффективные детекторы одиночных фотонов. Оптимальным выбором являются полупроводниковые лавинные фотодиоды (ЛФД), работающие в гейгеровском режиме. В докладе обсуждается необходимость создания российских ЛФД для квантовых систем связи.

The characteristics of MIS structures based on insulating PbSnTe:In films with compositions in the vicinity of a band inversion grown by molecular beam epitaxy (MBE) were studied. It has been shown that a number of their features can be caused by a ferroelectric phase transition with a Curie temperature in the range T ≈ 15–20 K.

The dependence of the photoconductivity sign on the bias voltage, intensity and duration of illumination was studied in PbSnTe:In films in the space charge limited current regime. The role of traps with a complex energy spectrum, including the surface traps, in the observed effects is discussed

This paper reports a study of the current–voltage (I–V) features of the p-i-p structures based on Pb1–xSnxTe:In films with the tin content х ≈ 0.31 in which the metal–insulator transition occurs. It is shown that the photocurrent is the hole current under light interband excitation, and electron trapping is dominant. The experimental and theoretical data are compared.

AbstractBased on the notions that PbSnTe:In is a direct-gap semiconductor, the radiative-recombination lifetime is calculated, and the photocurrent relaxation and dependences of the instantaneous electron and hole lifetime are calculated under the assumption that PbSnTe:In is a disordered structure containing capture centers. These calculations explain such experimentally observed peculiarities of PbSnTe:In as a high photosensitivity in a wide wavelength range, pinning of the Fermi level, and long-term photocurrent relaxation. Calculations are also compared with experimental data and the possible parameters of photodetectors are evaluated.

This paper presents a review of studies of the photoelectric properties of PbSnTe:In films obtained by molecular beam epitaxy and photosensitive structures in the far infrared and submillimeter ranges based on these films. The parameters of photodetector arrays of this type and detectors based on doped semiconductors and superconductors are compared. One-dimensional (2×128 elements) and two-dimensional (128 × 128 elements) PbSnTe:In based arrays with a sensitivity threshold of ~22 μm and an operating temperature of T ≤ 16 K are implemented. Under background-free conditions, the noise equivalent power (NEP) was NEP ≤ 10−18 W/Hz0.5 at T = 7 K for a black body radiation source at TBB = 77 K. In the submillimeter range of the spectrum, sensitivity to laser radiation with a wavelength λ ≤ 205 μm and a value NEP ≤ 10−12 W/Hz0.5 was observed without optimization of the design of the photosensitive element and minimization of the measurement circuit noise. The directions of the development of PbSnTe:In based radiation detectors are considered..

This review analyzes the current state of research pertaining to the design of thermal and photon far-infrared and submillimeter array detectors. Threshold detector characteristics are compared and the application potential of photodetectors is explored.