High Power, Tunable Waveguide CO₂ Lasers

Abstract

The CO₂ laser is the most popular source of coherent mid-infrared radiation and is widely used both for scientific and technological applications. High efficiency and high power can be obtained either in CW and in pulsed regime. The emitted wavelength can be tuned over many different lines in the interval 9–11 μm by using a diffraction grating as an intracavity dispersive element. The CO₂ laser can also be frequency stabilized with high reproducibility. As a secondary frequency standard it plays a fundamental role in the measurement of the speed of light and in the new definition of the unit of length. Other important scientific applications are plasma generation, molecular multiphoton dissociation, isotopic separation, LIDAR, molecular spectroscopy, and generation of medium and far-infrared (MIR,FIR) coherent radiation either by stimulated Raman scattering or resonant optical pumping of molecular transitions. By means of the molecular FIR laser optically pumped by the CO₂ laser this spectral region was covered for the first time with thousands of CW laser lines of relatively high power so that the laser spectroscopy has been extended down to the microwave region ¹.