High Order Overtone CO Laser

Abstract

The paper presents the results of modeling the high overtone CO laser as well as the experimental results of a particular electric-discharge carbon monoxide broadband overtone laser that has been developed.. The laser is capable of operating on CO first overtone bands only (∆v = 2) and delivering up to 12 W cw power at efficiencies of up to 5%. The laser output consists of vibrational-rotational lines of the v = 9→7 to v = 35→33 overtone bands and covers the spectral range between 2.6 to 3.9 microns. A kinetic modeling code has been developed to predict the power, efficiency, and the output spectrum of overtone CO lasers. According to the calculation, a positive gain on higher overtone transitions (∆v = 3 and 4) may also be achieved by creating a total inversion population between vibrational levels of CO in the laser medium. Such total inversion can be created by lasing on certain fundamental (∆v = 1) transitions and burning a ‘hole’ in the vibrational distribution function. Lasing can be achieved in both c.w. and Q-switched modes. A design study of high order overtone CO laser has been performed and two possible embodiments of its design are proposed.