Application Of Systems With Total Internal Reflection At Novosibirsk Free Electron Laser For Spectroscopy In The Terahertz Range

Attenuated total reflection (ATR) spectroscopy is widely used in the visible and infrared spectral ranges. Progress in the development of laboratory scale monochromatic sources of terahertz radiation, such as quantum cascade lasers, suggests that in the near future this kind of spectrometers will be widely spread in the terahertz range. For this reason, the development of ATR based methods and devices is highly relevant. In this paper, we discuss the features of the use of ATR spectroscopy in the terahertz range, and describe some of the optical systems, designed for experiments at the Novosibirsk free electron laser (NovoFEL). We show that in the terahertz range the ATR spectroscopy has a number of significant advantages over the absorption spectroscopy. As an example, we are discussing the possibility of using terahertz polarimetry to develop a method for early diagnosis of cancer via the detection of left-handed to right-handed polysaccharide enantiomers ratio. Spectra of selected polysaccharides were recorded with a standard Fourier spectrometer using developed by us an ATR unit. The possibility of studying the polarization characteristics of polysaccharides in aqueous solutions using spectrally selective polarimeter with the NovoFEL as a tunable radiation source was demonstrated.