Ohtake S, Yoshikawa S, Imasaka T
Appl Opt. 1995 Jul 20;34(21):4337-42. doi: 10.1364/AO.34.004337.
A circularly polarized, monochromatic laser beam is focused into a Raman cell, which contains hydrogen to generate rotational stimulated Raman emission. After linear polarization, this two-color (separated by 587 cm(-1)) laser beam is focused several times into a second Raman cell that is filled with hydrogen to generate a multifrequency laser emission. Many rotational and vibrational lines are generated efficiently by this multipass effect. Eighteen colors that are quasi equally spaced with a rather flat intensity distribution are generated throughout the entire visible region. The present multifrequency laser emission may be advantageously used for illumination in a higher-grade display, such as a laser light show.