Second Stokes component generation in the SRS of chirped laser pulses

An experimental investigation was made of optical schemes for the generation of the second Stokes component in the SRS of broadband chirped laser pulses in high-pressure gases. Measurements were made of the energy conversion efficiency and the spatial characteristics of the light beam of the second Stokes component for one- and two-fold focusing of the pump radiation into the gas-filled cell as well as in schemes involving a quartz capillary and two gas-filled cells. The highest energy efficiency of conversion to the second Stokes component was attained in the case of cascade generation in the optical scheme with two pressurised-gas cells. In the SRS in hydrogen in this scheme, the Ti:sapphire laser radiation with a wavelength of 0.79 μm was converted to the 2.3-μm second Stokes component with an efficiency of 8.5%.