A novel approach anticipates real time acquisition of spatially resolved polarization data to facilitate fast cross-sectional tracing collagen-related birefringence in skin down to reticular dermis, i.e. up to the depth of a few hundreds micrometers. It is based on a unique integration of a static-type interferometer in a time domain system intended for polarization-sensitive optical coherence tomography (PS-OCT). The design concept avoids any movable parts to evolve fringes over the traced depth, and exploits liquid crystal bistable switches to rapidly discriminate between orthogonal polarization components of the analyzable signal. The signal is transmitted through a polarization maintaining fiber and detected, by turns, in the single optical channel by the same line camera of appropriate format. The approach relies on the statements proven in the art. In particular, time-domain PS-OCT based on coherent detection of the fringe intensity in orthogonal polarization components of reflected signal allows identifying at least qualitatively collagen depletion regions in subsurface skin layers. Polarization state of light backscattered from sufficiently shallow depth in skin is defined mostly by linear birefringence of collagen fibers. Propagation of light in such linearly birefringent medium satisfies the reciprocity principle in optics.
We have constructed, theoretically described and studied characteristics of plane-parallel geometry KTP optical parametric oscillator for conversion Nd:YAG laser radiation into eye- safe region (1.57 micrometers ). 50% conversion efficiency and 12.5 mJ generation energy have been attained.
It's noted that in spite of a wide variety of record results reached up till now for experimental models of Titanium-Sapphire (Ti-Sa) lasers, there is a great market demand for commercial models of nanosecond pulsed lasers, as well as of ultrafast modelocked CW lasers. The commercial models of research-quality nanosecond tunable Ti-Sa lasers developed and manufactured by SOLAR are considered.
An experimental model of a polarization interferometer (PI) is developed to be used as a basic functional module for a static type, i.e., multichannel, Fourier transform spectrometer (MCFTS) with high optical throughput and reasonable resolution for simultaneous recording of transient spectra of faint sources in the wide visible range 400 - 700 nm. Rigid axial configuration without any mechanical scanning provides compact and robust construction, which meets requirements of a number of laboratory and field applications.