Accession Number : ADA118877

Title :   Continuously-Tunable High-Repetition Rate RF-Excited CO2 Waveguide Laser,

Corporate Author : NORWEGIAN DEFENCE RESEARCH ESTABLISHMENT KJELLER

Personal Author(s) : Loevold,Stian

PDF Url : ADA118877

Report Date : Jul 1982

Pagination or Media Count : 101

Abstract : The concept of pumping a CO2 laser with a radiofrequency discharge at multiatmospheric pressures in order to obtain continuous frequency tuning has been investigated both theoretically and experimentally. Experimentally 40.68 MHz rf-excitation of discharges between parallel plate electrodes with up to 7-8 kW peak rf-power has been investigated. Emphasis has been laid on how to attain a stable glow-discharge with sufficiently long duration before arcing for integration of enough rf-power in the discharge to reach threshold for laser oscillation. A 10 atm rf-excited CO2 waveguide laser has been developed. With no dispersive elements in the laser resonator and with a 2% output coupler, input rf-power threshold for laser oscillation was 2 kW at 10 atm. Peak output power was 1.5 kW for 7-8 kW input rf-power. The output pulse has the form of a 300 ns duration gain-switched pulse followed by a tail at lower power. An efficiency (input rf-energy/laser output-energy) of 2% has been measured for the gain-switched pulse. The laser has been operated with pulse repetition rates in excess of 1 kHz, limited primarily by the available gas-flow capacity. Continuous frequency tuning between the R(12) and R(14) lines in the 10.4-micrometer band has been demonstrated. (Author)

Descriptors :   *Carbon dioxide lasers, *Infrared lasers, *Tunable lasers, *Pulsed lasers, *Glow discharges, Barometric pressure, Pulse rate, Waveguides, Radiofrequency pulses, Electrodes, Gas flow, Time, Very high frequency, Plates, Dispersions, Frequency, Switching, Resonators, Parallel orientation, Nitrogen, Output, Oscillation, Ionization, Pulses, Low power, Tuning, Lasers, Stability, Helium, Gain, Norway

Subject Categories : Lasers and Masers
      Plasma Physics and Magnetohydrodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE