Roman Ozhegov

В работе проведено сравнение точности дальнометрии лидарных архитектур прямого времени пролета (dToF) и вне прямой видимости (NLOS), обе из которых используют сверхпроводящий нанопроволочный детектор одиночных фотонов (SNSPD). Обе системы работают на длине волны 1550 нм с импульсным лазером длительностью 50 пс и методом коррелированного во времени счета одиночных фотонов (TCSPC). Конфигурация dToF обеспечила точность около 100 мкм на расстоянии 10 м, тогда как конфигурация NLOS обеспечила точность 500 мкм для скрытого объекта, расположенного на 0,5 м за отражающей стеной. Сравнение показывает, что dToF обеспечивает превосходную точность благодаря прямому оптическому пути, тогда как NLOS страдает от дополнительного временного уширения, вызванного многократным рассеянием. Полученные результаты дают количественные рекомендации для выбора подходящей архитектуры в зависимости от требований применения.

The rapid development of photonic integrated circuits (PICs) and their applications in various fields of science and technology requires the creation of easy-to-manufacture high-speed integrated detectors. In this work, we fabricated and studied planar waveguide-integrated bolometers based on a thin film of single-walled carbon nanotubes (SWCNTs) on the silicon nitride platform. This bolometer showed good internal responsivity and a high bandwidth >1 GHz. In-depth analysis allowed us to retrieve the main parameters of the SWCNT film that govern the bolometric response that can be difficult to measure directly. The results obtained show a promising prospect of using SWCNT bolometers for PIC applications.

Today, a lab-on-a-chip is one of the most promising ways to create sensor devices for gas and liquid analysis for environmental monitoring, early diagnosis, and treatment effectiveness assessment. On the one hand, this requires a large number of measurements and, on the other hand, involves minimum consumption of the test analytes. Combination of highly sensitive photonic integrated circuits (PICs) with microfluidic channels (MFCs) is necessary to solve this problem. In this work, PICs based on a silicon nitride platform integrated with MFCs for studying liquids and gases were developed. Different concentrations of isopropanol in de-ionized water were used as the analyte. Based on this, the sensitivity (S) and detection limit (DL) of the analyzed solution were evaluated. Entire system calibration was carried out to calculate S and DL, considering experimental and numerical simulation data. This development may be of interest as a promising platform for environmental monitoring and realization of point-of-care strategy for biomedical applications.

This paper investigates the thermo-optical (TO) effect of misaligned polymer wire bonds (PWB) connecting planar silicon nitride waveguides. To characterize the fabricated devices, we measured the optical transmission through PWBs by changing the chip temperature in the range from 30°C to 80°C. We used an experimental setup, which included a tunable laser source in the 1510-1620 nm range and a changeable temperature stage. By gradually changing the temperature of the sample, we measured the transmission parameter through the reference arm and the arm with PWB. We found that the TO coefficient equals 837 pm/°C, respectively, with the change resonance wavelength. The results can be used to design complex optical interconnections inside and between chip and show the thermal stability of such interconnection.

We present evidence that in the sub-THz frequency band, human skin can be considered as an electromagnetic bio-metamaterial in which its natural emission is a product of skin tissue geometry and embedded structures. Radiometry was performed on 32 human subjects from 480 to 700 GHz. Concurrently, the subjects were exposed to stress, while heart pulse rate (PS) and galvanic skin response (GSR) were also measured. The results are substantially different from the expected blackbody radiation signal of the skin surface. PS and GSR correlate to the emissivity. Using a simulation model for the skin, we find that the sweat duct is a critical element. The simulated frequency spectra qualitatively match the measured emission spectra and show that our sub-THz emission is modulated by our level of mental stress. This opens avenues for the remote monitoring of the human state.

We present an active anti-latching system for superconducting nanowire single-photon detectors. We experimentally test it against a bright-light attack, previously used to compromise security of quantum key distribution. Although our system detects continuous blinding, the detector is shown to be partially blindable and controllable by specially tailored sequences of bright pulses. Improvements to the countermeasure are suggested.

We present an active anti-latching system for superconducting nanowire single-photon detectors. We experimentally test it against a bright-light attack, previously used to compromise security of quantum key distribution. Although our system detects continuous blinding, the detector is shown to be partially blindable and controllable by specially tailored sequences of bright pulses. Improvements to the countermeasure are suggested.