Stimulated temperature scattering of eye-safe laser pulses

Summary form only given. Stimulated temperature scattering (STS) has been known for many years. However, in practice it is difficult to use STS because of competing nonlinear processes, primarily stimulated Brillouin scattering SBS, which have lower threshold in the visible and near infrared regions. On the other hand, the backward (SBS) threshold increases with wavelength making application of SBS of nanosecond pulses with moderate energy at wavelengths above 1.3 /spl mu/m inefficient due to /spl lambda//sup 3/ scaling of the threshold. In a new generation of eye-safe lasers their spectral linewidth is relatively broad that also contributes to the increase of the SBS threshold. Since the increase of STS with wavelength is not so dramatic one can expect prevailing of STS over SBS at longer wavelengths. Our goal was to verify that STS can be reliably excited in eye-safe region, and to find STS media, which being not exotic or toxic, might be suggested as quite effective phase-conjugators for this region. We used a Nd:YAG laser as a pump and calcite crystal as the wavelength shifter to generate radiation at either 1384 nm or 1628 nm.