<title>Recent progress in high-power para-H<formula><inf><roman>2</roman></inf></formula> and ortho-D<formula><inf><roman>2</roman></inf></formula> Raman lasers</title>

Abstract

A variety of infrared rotational Raman lasers developed at RIKEN for the purpose of molecular laser isotope separation are described. One of the major advances is that annular pump beams from an unstable resonator of a TEA CO<SUB>2</SUB> power oscillator can be efficiently converted to Stokes beams in a multiple pass cell, which results in an increase in the total efficiency of the para-H<SUB>2</SUB> Raman laser system. The annular pump beams are used to generate second Stokes waves in ortho-D<SUB>2</SUB>, which provide a number of lines different from those of first Stokes waves in para-H<SUB>2</SUB> in the 13 - 18 micrometer spectral range. First Stokes generation using the S(2) transition of ortho-D<SUB>2</SUB> at room temperature is also described.