Measurements on the Stimulated Raman Effect in H2 in Terms of Laser Oscillator and Amplifier Theories

The growth of Raman-shifted Stokes radiation as a function of various parameters, (such as laser pump power, cavity reflectivity, etc.) has been studied in H2, a nonbeam trapping medium. It is demonstrated that growth of the Stokes converted output follows normal laser-oscillator dynamics. On this basis the previously observed ``anomalous'' gain which is not associated with beam trapping can be explained. If a strong external Stokes signal is injected, the Raman converting medium acts as an amplifier until the laser pump power achieves an intensity sufficient to produce oscillations at the Stokes frequency. The growth of Stokes radiation was examined under dispersive conditions such that anti-Stokes radiation was not produced, thus lending itself to a straightforward rate-theory type of analysis.