Increased inversion efficiency in optically pumped two-level molecular systems.

ABSTRACT

It is shown how, under certain circumstances, optically pumping an R-branch transition at high J number in a molecular gas may result in a situation in which over half of the particles are in the excited vibrational manifold. This can lead to increased gain in transitions to intermediate-lying states and increased fluorescence signal in laser-induced- fluorescence experiments. In addition, gain can also be obtained on pumping in band transitions that have frequencies smaller than the pump-laser frequency. Such an arrangement can be employed to obtain a wavelength shift.