Investigation of stability and efficiency of SRS-based sources of radiation for spectroscopy applications

In the last few years radiation sources on the basis of stimulated Raman scattering (SRS) have been sufficiently widely used in spectroscopy. Of great importance therein are high efficiency of radiation conversion to one, usually first Stokes (FSC) or anti-Stokes (FASC) component of SRS, small divergency of converted radiation flux, stability of reproduction of its energy and time characteristics. SRS is a process of amplification of quantum noises. Therefore, quantum noise is one of the sources of fluctuation of temporal, energy, and spectral parameters of converted light. The stability of SRS radiation pulses is strongly influenced by fluctuations of laser radiation parameters. The design features of Raman shifters and properties of scattering medium influence SRS efficiency and converted flux divergency. As a result, fluctuations of converted radiation parameters can reach dozens percent, radiation divergency can be about 10-2 rad, and efficiency of SRS-conversion to one component doesn't usually exceed 10 divided by 20%. In our paper results on experimental study of SRS regimes and geometrical factors influence on statistical properties (fluctuations of energy and instantaneous intensity) of pulses of forward, backward FSC, FASC of SRS and depleted pump as well as on efficiency of SRS process are briefly presented. On the basis of the investigations made we discuss the ways of creating SRS-based radiation sources with high quantum efficiencies (>= 70%) of conversion into FSC, close to diffraction divergency (approximately equals 0.5 mrad) of converted flux and high stability (variation coefficient