Generation of vibrational and rotational emissions by four-wave Raman mixing using an ultraviolet femtosecond pump beam.
A femtosecond KrF excimer laser is focused into molecular hydrogen to generate a multifrequency laser beam, consisting of many vibrational and rotational lines, in a transient Raman regime. The intensity distribution is unchanged from 5 to 13 atm, in contrast to the case of nanosecond laser pump. The efficiency for generation of the rotational lines is improved by increasing the peak power, especially at longer wavelengths, indicating power-dependent and wavelength-dependent behavior of this effect, as expected from theory.
Irie
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Imasaka
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