Continuously tunable TEA CO2 laser

A resonator with a diffraction grating was used at almost grazing incidence to provide continuous tuning of the frequency of a pulsed CO₂ laser having an active-mixture pressure below atmospheric. Using a CO₂:N₂:He = 1:1:7 mixture at a pressure of 0.9 atm, the 10P(20) line could be tuned by 2.6 GHz and the output energy at the center of the gain profile of the vibrational-rotational transition was 230 mJ. An investigation was made of the dependences of the reflection coefficients of diffraction gratings with 75, 100, and 150 lines/mm, in different diffraction orders, on the angle of incidence of s-polarized radiation.