Oleg Kiselev

Superconducting Integrated Submillimeter Receiver for TELIS

In this report an overview of the results on the development of a single-chip superconducting integrated receiver for the terahertz limb sounder (TELIS) balloon project intended to measure a variety of stratosphere trace gases is presented. The superconducting integrated receiver (SIR) comprises in one chip a planar antenna integrated with a superconductor-insulator-superconductor (SIS) mixer, a superconducting flux flow oscillator (FFO) acting as local oscillator (LO) and a second SIS harmonic mixer (HM) for FFO phase locking. As a result of the FFO design optimization a free-running linewidth between 9 and 1.5 MHz has been measured in the frequency range 500-710 GHz resulting in phase-locking of 35 to 95% of the FFO power correspondingly. A new generation of the SIR devices with improved FFO performance and optimized interface between FFO and SIS/HM has been developed and comprehensively tested. As a result all required TELIS parameters were demonstrated. Phase-locked FFO operation over entire SIR channel frequency range has been realized, spectral resolution below 1 MHz has been confirmed by gas cell and CW signal measurements. An uncorrected double side band (DSB) noise temperature below 250 K has been measured with the phase-locked FFO. The intermediate frequency bandwidth 4-8 GHz has been realized. To ensure remote operation of the phase-locked SIR several procedures for its automatic computer control have been developed and tested.

Superconducting Integrated Terahertz Spectrometers

A superconducting integrated receiver (SIR) comprises all of the elements needed for heterodyne detection on a single chip. Light weight and low power consumption combined with nearly quantum-limited sensitivity and a wide tuning range of the superconducting local oscillator make the SIR a perfect candidate for many practical applications. For the first time, we demonstrated the capabilities of the SIR technology for remote operation under harsh environmental conditions and for heterodyne spectroscopy at atmospheric limb sounding on board a high-altitude balloon. Recently, the SIR was successfully implemented for the first spectral measurements of THz radiation emitted from intrinsic Josephson junction stacks (BSCCO mesa) at frequencies up to 750 GHz; linewidth below 10 MHz has been recorded in the high bias regime. The phase-locked SIR has been used for the locking of the BSCCO oscillator under the test. To extend the operation range of the SIR well above 1 THz, a new technique for fabrication of high-quality SIS tunnel junctions with gap voltage Vg up to 5.3 mV has been developed. Integration of a superconducting high-harmonic phase detector with a cryogenic oscillator opens a possibility for efficient phase locking of the sources with free-running linewidth up to 30 MHz that is important both for BSCCO mesa and NbN/MgO/NbN oscillators.

The Stimulated Scattering of Solitons on a Resonance

Abstract We investigate a propagation of solitons for nonlinear Schrödinger equation under small driving force. The driving force passes through the resonance. The process of scattering on the resonance leads to changing of number of solitons. After the resonance the number of solitons depends on the amplitude of the driving force.

Superconducting integrated THz receivers: development and applications

A Superconducting Integrated Receiver (SIR) comprises on one chip all elements needed for heterodyne detection: a low-noise SIS mixer with quasioptical antenna, a Flux-Flow Oscillator (FFO) acting as a Local Oscillator (LO) and a second SIS harmonic mixer (HM) for the FFO phase locking. Light weight and low power consumption combined with nearly quantum limited sensitivity and a wide tuning range of the FFO make SIR a perfect candidate for many practical applications. In particular, the SIR developed for novel balloon borne instrument TELIS (TErahertz and submillimeter LImb Sounder) covers frequency range 480 - 650 GHz. As a result of recent receivers optimization the DSB noise temperature was measured as low as 120 K for the SIR with intermediate frequency (IF) band 4 - 8 GHz. The capability of the SIR for high resolution atmospheric spectroscopy has been successfully proven with scientific balloon flights from Kiruna, North Sweden. Diurnal cycles of ClO and BrO has been observed with BrO line level of only about 0.5 K. Possibility to use the SIRs for analysis of the breathed out air at medical survey has been demonstrated.

Resonant excitation of nonlinear waves

We construct a special asymptotic solution for the forced Boussinesq equation. The perturbation is small and oscillates with a slowly varied frequency. The slow passage through the resonance generates waves with the finite amplitude. This phenomenon is described in details.

Scattering of trajectories at a separatrix under autoresonance

The subject of this paper is solutions of an autoresonance equation. We look for a connection between the parameters of the solution bounded as tu2009 →−∞, and the parameters of two two-parameter families of solutions as tu2009 → ∞. One family consists of the solutions which are not captured into resonance, and another of those increasing solutions which are captured into resonance. In this way we describe the transition through the separatrix for equations with slowly varying parameters and get an estimate for parameters before the resonance of those solutions which may be captured into autoresonance.

Autoresonance in a dissipative system

We study the autoresonant solution of Duffings equation in the presence of dissipation. This solution is proved to be an attracting set. We evaluate the maximal amplitude of the autoresonant solution and the time of transition from autoresonant growth of the amplitude to the mode of fast oscillations. Analytical results are illustrated by numerical simulations.

The autoresonance threshold in a system of weakly coupled oscillators

A system of two weakly coupled oscillators is investigated. It is shown that under an external periodic perturbation a capture into resonance may occur. A description of this effect by the methods of asymptotic analysis, as well as a numerical simulation, is presented. An explicit formula for the threshold value of the perturbation amplitude at which the resonance occurs is obtained.

Superconducting Integrated THz Receiver

A Superconducting Integrated Receiver (SIR) developed for balloon borne instrument TELIS covers frequency range 450–650 GHz. The DSB noise temperature was measured as low as 120 K. The SIR application for high resolution spectroscopy of breathed out air has been proven.

Application of superconducting integrated receiver in the TELIS instrument for the spectroscopic study of atmosphere

A superconducting integrated receiver (SIR) (superheterodyne receiver) is developed for detection of radiation in a frequency range of 450–650 GHz. The SIR is used as a detector in the Terahertz Limb Sounder (TELIS) instrument that is mounted on a high-altitude balloon for the study of the atmospheric composition in the terahertz frequency range using limb sounding. The TELIS instrument and its detectors are described, and several results of the measurements in Polar Regions in 2009–2014 are presented