Stimulated electronic Raman and hyper-Raman scattering in potassium vapor

Stimulated electronic Raman scattering and hyper-Raman processes in potassium vapor near the D1 and D2 lines have been observed using a stable resonator and pulsed laser excitation. First and second order Stokes and anti-Stokes lines were observed simultaneously and independently for a pump laser tuning range exceeding 70 cm−1. The output energy increases by more than a factor of 103 as the potassium concentration increases from 0.25 to 2.2×016 cm−3. When the pump is tuned between the K D1 and D2 lines, an efficient hyper-Raman process dominates with a slope efficiency that exceeds 10%. The threshold for the hyper-Raman process is about 6 mJ per pulse, or 3.8 MW/cm2 peak intensity. This Raman shifted laser may be useful as a target illuminator or atmospheric compensation beacon for a high power diode pumped alkali laser.