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In this paper we describe the terahertz imagers which characteristics are adequate for measurement of high power terahertz radiation. Three imaging techniques were employed on the Novosibirsk terahertz free electron laser (NFEL): near-infrared thermograph, thermosensitive visible light interferometer, and "a thermal image plate". All this methods are widely(More)
Imaging in the terahertz spectral range is a subject of special interest for many applications. In this paper, we describe two methods for the THz imaging with a high power free electron laser. The first method is based on the transformation of THz radiation to near-infrared radiation and visualization with a thermograph. The second method is based on the(More)
An uncooled micromolometer matrix camera has been developed for IR and THz high-speed imaging. The 120 x 160 matrix consists of resistive vanadium oxide elements on a silicon nitride bridge. The element size is 46 x 46 micron at the array period of 51 micron. We describe device fabrication process and matrix operational characteristics. Application of the(More)
Osteoporosis is a major cause of morbidity of older people. Direct financial expenditure for the treatment of osteoporotic fracture in the U.S. is estimated at $10-$15 billion per year. Though there are a number of methods for diagnostics of osteoporosis, X-ray radioscopy, NMR, element analysis, densitometry, etc., the development of new methods, which are(More)
High-power Novosibirsk free electron laser, generating coherent monochromatic tunable radiation within the spectral range from 120 to 240 micrometers, is used for the shadwography of semi-transparent objects. Toepler and holography systems, which are under construction, will enable spectrally-selective imaging at the laser beam diameter of about 10 cm.
Novel approach to controlling polarization of THz radiation is introduced. Polarization plane rotation of transmitted wave by a monolayer of precise microhelices was demonstrated by experiments on the Novosibirsk free electron laser. It had strongly resonant character. Modulation of polarization opens up new possibilities in communication, biomedical,(More)
During the past year, generation characteristics of the Novisibirsk terahertz free electron laser were growing up. It generates now coherent radiation tunable in the range 120-170 /spl mu/m at the repetition rate of 2.8-11.2 MHz. Maximum average output power reaches 400 W at 11.2 MHz. Laser radiations are transmitted through a 14-m optical beamline to the(More)
Description of an original two-beam ATR-spectrometer for study of biomolecule spectra in solutions and powders is given in the paper. This scheme enables to overcome inherent to the ATR-spectrometers ambiguity in the determination of absorption coefficient from experimental data.
The first stage of Novosibirsk high power free electron laser (FEL) was commissioned in 2003. It is based on normal conducting CW energy recovery linac. Now the FEL provides electromagnetic radiation in the wavelength range 120-180 micron. The average power is 100 W. The measured linewidth is 0.3%, which is close to the Fourier-transform limit. The assembly(More)