P. K. Nesterov

260 GHz quasioptical setup for EPR and DNP experiments on the 9.2 Tesla DNP/NMR/EPR spectrometer

Transmission of microwave signals under low-losses conditions is highly demanding task in sub-mm EPR and DNP spectroscopy. We have designed and built a quasioptical setup in the Michelson interferometer configuration using oversized metallo-dielectric waveguides (MDW) of a square-shape cross-section and components such as attenuators, beam splitters, wavemeter, tapers to fundamental TE10 mode which have extremely low losses in sub-mm wave range. Following features of the setup such as total transmission losses below 2 dB from the source port to a resonator with a sample inside the cryomagnet; fine balance tuning between signal and reference channels affording up to 36 dB background signal suppression, linear-to-circular polarization conversion with a possibility to tune its phase, which allows effective suppression of reflected signal with respect to induction signal; switching between two microwave sources; and high power handling up to 20 Watt helped to reach high performance of the 9.2 Tesla DNP/NMR/EPR spectrometer. First liquid-state DNP results on nitroxide radicals in water will be presented.

Application of the method of integral functionals for evaluation of the CFRP polarization-frequency response in sub-THzFrequency range and experimental verification of the results

The composite materials, such as fiber-glass and CFRP, are increasingly used for manufacturing of structural components in aeronautics industry due to their high durability and reduced corrosion in comparison with other materials. This leads to aerodynamic characteristics improvement, reduction of aircraft weight, essential fuel economy and, as a result, to reduction of exhaust gas emission and exploitation costs and rise of flight safety. At the same time, adhesive bonding techniques are increasingly used in aeronautic industry for manufacturing of composite structural components instead of traditional rivet-based assembly [1]. Using of terahertz (THz) electromagnetic radiation (0.1...10 THz) is one of the promising methods for non-invasive testing of composites.

Terahertz Low-Temperature Receivers for the Quasi-Optical Interferometers

Low-temperature terahertz receivers intended for operation as a part of laser quasi-optical interferometers using basic transmission line as a hollow dielectric beam guide are designed. Examples of such receivers presented in this article include single-channel low-temperature receiver and four-channel low-temperature receiver.