Study On Energy Extraction Efficiency Of HF Chemical Laser With MOPA Configuration

Chemical laser is a kind of high power laser which produces very high power laserby changing the chemical energy directly into optical energy. The traditional chemicallaser using a single unstable resonator would take a big risk in engineering whilepursuing the high power output. Chemical laser with the master oscillator and poweramplifier (MOPA) configuration, which can overcome the engineering difficultiesbrought by the unstable resonator, is a good solution to achieve high output power withgood beam quality. At the present time, the study of high power chemical laser,especially the HF/DF chemical laser, with a single-pass MOPA configuration is at thebeginning in our country. And there is a poor knowledge about the energy extractionefficiency of the chemical laser. So, it’s valuable to have a study on the energyextraction efficiency of the chemical laser with MOPA configuration, to figure out thefactors that affect the energy extraction efficiency of the amplifier, and to find a feasibleway to improve the energy extraction efficiency in the experimental research. And thiscan be a useful tool for optimizing and improving the high power HF/DF chemicallaser.In this article, the rate equations of the HF chemical laser with a MOPAconfiguration have been simplified as a rate equations model with two spectral-linescascade. And the solutions of the rate equations of the master oscillator and the poweramplifier have been solved in the stable condition. According to the model, acalculation program is written, and the effect of the component and the relative intensityof the spectrum, the input power, and the length of the gain medium on the laser areanalyzed, and the calculated results agree well with the experimental results.Considering some errors may exist in the model, a simplified rate equations model withfour spectral lines is rebuilt, and the stable solution has been solved. Comparison of thetwo simplified models has been made.By constructing the MOPA configuration of the discharge-driven CW HF laser, theenergy extraction efficiency has been studied. The output spectrum of the masteroscillator of the system has been measured and the character of the variation of thespectrum has been figured out. By using the blazing grating within the HF spectrum, AHF chemical laser with two HF spectral lines-selected has been designed theoretically,considering the absorption of the atmosphere and the energy extraction efficiency ofdifferent HF spectral lines. At last, the spectrum, power amplification and the energyextraction efficiency of the amplifier have been measured. In summary, the change ofthe spectrum of the laser after passing the amplifier is rather small; the poweramplification decreases with the input power increasing, and increases with the flowrate of the gases increasing; and the energy extraction efficiency increases with the input power increasing, and increases with the flow rate of the gases increasing.