Waveguide CO/sub 2/ laser gain: dependence on gas kinetic and discharge properties

Journal Article · Thu Apr 01 04:00:00 EST 1976 · IEEE J. Quant. Electron.; (United States)

DOI:https://doi.org/10.1109/JQE.1976.1069125· OSTI ID:7182260

Cohen, S C

Using a simple rate equation approach the gas kinetic and discharge properties of waveguide CO/sub 2/ lasers is examined. The dependence of the population inversion and laser small-signal gain on gas pressure, gas mixture, pumping rate (discharge current), tube bore diameter, and wall temperature is calculated. The results indicate, for example, that at a pressure of 50 torr and a tube-bore diameter of 0.125 cm, the gain is optimized with a gas mixture in the ratio CO/sub 2/:N/sub 2/:He of 1:0.75:1.5. At higher pressures the gain is optimized by using more helium-rich mixtures. The dependence of laser tunability on the gas kinetic properties and cavity losses is calculated. It is found that for low-loss cavities the laser tunability may substantially exceed the molecular full width at half-maximum. Furthermore, the more helium-rich gas mixtures give greater tunability when cavity losses are small, and less tunability when cavity losses are large. The roles of the various gases in the waveguide CO/sub 2/ laser are the same as those in conventional devices. By contrast with conventional lasers, however, the waveguide laser transition is homogeneously broadened. Thus the dependence of gain on gas pressure and other kinetic properties differs substantially from that predicted by scaling results from conventional low-pressure lasers.

• Research Organization: Goddard Space Flight Center, Greenbelt, MD
• OSTI ID: 7182260
• Journal Information: IEEE J. Quant. Electron.; (United States), Journal Name: IEEE J. Quant. Electron.; (United States) Vol. QE-12:4; ISSN IEJQA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420300* -- Engineering-- Lasers-- (-1989)
CARBON DIOXIDE LASERS
GAIN
GAS LASERS
KINETICS
LASER CAVITIES
LASERS
TUNING
WAVEGUIDES