Fast-flow CO2 Laser Research Articles

Quasi-cw industrial CO2laser

A quasi-cw fast-flow electric-discharge CO2 laser is described. It emits radiation pulses of power up to 5 kW and duration exceeding 2 msec, with a continuously tunable repetition frequency of up to 500 Hz. The ultimate discharge characteristics and the power in a laser emission pulse are close to those for the cw pumping regime. Oscillograms of the output pulses are given. The considerable duration of the leading edge of the pulses (~ 1 msec) imposes a limit on the attainable repetition frequency. It is suggested that the marked delay of the leading edge of the emission pulses relative to the pump pulses is associated with the time dependence of the amplifying characteristics of the active medium along the flow direction and with the low specific input energies.

Investigation of the parameters of discharges in nitrogen and air intended for fast-flow CO2lasers

An experimental investigation was made of the energy characteristics of a gas-discharge chamber for a fast-flow CO2 laser. The dependences of the specific energy deposited in the discharge on the H2 additive, and on the temperature and velocity of the gas were demonstrated. The investigated discharge chamber was found to be capable of operating effectively at pressures p ≥ 100 Torr.

Investigation of the optical inhomogeneities of the active medium of a fast-flow CO2laser with mixing

An experimental investigation was made of the gas temperature, spatial distribution of the gain, and optical inhomogeneities in a fast-flow CO2 laser with mixing. The results obtained were compared with those calculated using a model of instantaneous homogeneous mixing. An estimate was obtained of the influence of optical inhomogeneities of the active medium on the spatial characteristics of the output radiation.

Procedure for diagnosing processes in the discharge chamber of a fast-flow CO2laser

A semiempirical procedure was developed for investigating the discharge-chamber characteristics of a fast-flow CO2 laser. It was found to be sufficient merely to measure the average specific input energy and the gas temperature, averaged over the cross section of the chamber. It was noted that the calculation of the operating efficiency of the discharge chamber was insensitive to a lack of precision in the experimental data.

Characteristics of a CO2laser excited by a capacitative ac discharge

An experimental study was made of a model of a steady-state fast-flow CO2 laser excited by a 10 kHz ac capacitative discharge. The results of an optimization of the laser operating regimes agree with those obtained from calculations. According to these results a commercial laser with a power of ~20 kW, an overall efficiency of ~15%, and a specific output energy of ~40?45 J/g can be made utilizing the specific parameter levels achieved in this work.

Investigation of the efficiency of pumping of fast-flow CO2lasers by an alternating-current discharge

An experimental investigation was made of the efficiency of pumping of a fast-flow CO2 laser by an alternating-current discharge of 10 kHz frequency. A specific energy input of 300 J/g and a total vibrational efficiency of at least 50-60% were achieved in such a discharge. An analysis was made of the advantages of the proposed excitation method in various applications of lasers in technology.

Investigation of an electric discharge chamber of a fastflow CO2laser

An experimental investigation was made of the electric discharge chamber of a fast-flow CO2 laser utilizing an air-CO2 mixture. The molecular gas pressure could be increased to 100?130?Torr retaining a fairly high specific energy input. The results indicated the existence of an optimal distance between the cathode elements. An increase in the downstream length of the chamber failed to produce a corresponding increase in the energy input. The maximum energy input was determined as a function of the gas pressure, gas velocity, and length of the discharge zone.

Stability of stimulated emission from a fast-transverse-flow CO2laser

An investigation was made of the stability of stimulated emission from a fast-flow CO2 laser in which the active medium traveled at right-angles to the optic axis of the resonator. Amplitude modulation of the output radiation was observed in stable and unstable resonators. This modulation could not be explained by fluctuations of the gain at the entry to the resonator.

Atmospheric-air continuous-wave CO2laser

A description is given of a fast-flow open-cycle CO2 laser utilizing a mixture of atmospheric air and carbon dioxide at pressures of 40?100?Torr. The results are given of measurements of the output radiation power as a function of the air humidity, CO2 concentration, and power supplied to the discharge chamber.

Calculation of the energy characteristics of an electricdischarge CO2laser

A model is proposed for the calculation of the output power of a fast-flow electric-discharge CO2 laser. The model can be applied to various laser systems (with self-sustaining and non-self-sustaining discharges, with addition of CO2 after passing through the discharge zone and without such addition). Quasi-onedimensional equations of gasdynamics are solved numerically together with equations of vibrational kinetics and allowance is made for the electrical excitation and stimulated transitions. An example of a calculation dealing with a CO2+N2+He laser is given.