TERAHERTZ SPECTROMETER BASED ON FEMTOSECOND LASER FOR A SCIENTIFIC RESEARCH

Terahertz (THz) spectrometer using femtosecond titanium-sapphire laser was developed. Experimental stand of the multi-purpose application was realized by using this spectrometer. It was realized to obtaining of the complex refractive index spectra of a large aperture samples and to research of the emission efficiency of THz radiation in a nonlinear optical media. It was proposed a method of spectrometer's absolute calibration by THz electrical field through an external control of polarization of the probe radiation. The threshold sensitivity to polarization changes was measured. It was 1.4 ± 0.5 μrad. It allows to estimate the threshold of THz field strength ~ 0.1 V/cm when zinc telluride crystal is used to detection. Width of the apparatus function of spectrometer was 9 GHz and it was estimated from the width of narrow lines of the water vapor in absorption spectrum of air gap. It well agrees with the theoretical estimation.

Keywords:
terahertz frequency range, nonlinear optical media, electro-optical sampling, timedomain spectroscopy, titanium-sapphire femtosecond laser. 
УДК 535-14 + 621.373.8 + 681.785

TERAHERTZ SPECTROMETER BASED ON FEMTOSECOND LASER FOR A SCIENTIFIC RESEARCH