Study Of Discharge Driven Continuous Wave Infrared Multi-band Chemical Laser

The concept of Discharge Driven Infrared Multi-band Chemical Laser (DIMCL) was brought forward in the thesis to fully uncover chemical lasers broad spectrum distribution in the mid-infrared region. Driven by high voltage discharge, the DIMCL can produce one or multi-lasing species on a single chemical laser device through gas feed interchange. If multi-band resonator technique (mirror interchange or using wide-band coated mirror) was employed, lasing of each band or mixed lasing on all bands can be realized. Overtone HF laser, HF laser, DF laser, HCl laser, DCl laser, HBr laser, and CO2 laser were considered at the initial stage.Based on Fluorine atoms generating technique, reactions of Fluorine atom with molecule Hydrogen and other Halogens were proposed to obtain high density Hydrogen and Halogen atoms. Hence the obstacle of carrying out multi-Hydrogen Halide laser on a single discharge driven chemical laser device was removed.Single discharge tube driven HF/DF laser was firstly built, 20 Watt in HF band and 12 Watt in DF band were obtained. The positive effect of injecting Helium diluent at the end of discharge tube was experimentally investigated. Choise of cavity parameters was studied. The conclusion is that the rule of maximizing fundamental mode volume can not be used exclusively to guide the selection of mirror curvature and cavity length. The diffraction loss induced by slit rectangular gas channel was investigated experimentally and theoretically, the analysis method had been utilized in the design process of infrared multi-band testbed.With the grating dispersive cavity under 1st order oscillating 1st order output scheme, single vib-roational specra line oscillating in HF and DF band was realized successfully. 11 lines of DF band had been selected, 8 lines of HF band had been selected and some lines nearly reached 1 Watt. Through adapting the distance between H2 injecting orifice and cavity axis, additional 3 lines in HF band were selected. The performance change of line-selected HF/DF laser induced by adapting relative distance between cavity axis and Hydrogen (Deuterium) injecting orifices was investigated. It is found that the different vib-rotational lines have different gain distributions, and its distinction exists even for the discharge driven chemical laser device with only millimeter order active length along flow direction. To select more lines and enhance power output of each spectra line, relative distance between cavity axis and Hydrogen (Deuterium) injecting orifices should be adjusted for each vib-rotational line.A multi-discharge tube driven infrared multi-band chemical laser testbed was built. Representative bands of HF/DF, HCl, and CO2 were realized on this testbed. 60 Watt, 100 Watt, 120 Watt had been obtained for HF laser according to different active width of 20cm, 40cm and 60cm. 50 Watt and 100 Watt had been obtained for DF laser according to different active width of 20cm and 60cm. For the discharge driven Hydrogen (Deuterium) Halide laser employing stable resonator, it was found that beam quality could be enhanced through higher active medium saturation level by increasing active width. Using much cheaper Chlorine as fuel, nearly 10 Watt 3.8 micrometer HCl laser was realized by H+Cl2 and H+ClF pump reactions without changing structure of discharge driven HF/DF laser. 12 Watt HF-HCl dual-band lasing were obtained using F-ClF-H2 chain reaction pump system. The power record of HCl laser was just limited by fuel supply restriction in the dischare tube. The negative effect of Chlorine atoms to the HCl laser realized by F-ClF-H2 system was pointed out. The limiting factor of each pump reaction system was clarified. It was assuring that 10 Watt order HCl lasing could be obtained, if the two pump reaction was combined and new running scheme was employed. Transfer chemical CO2 laser and transverse flow mixing discharge CO2 laser were studied experimentally. Though limited by heat endurance of cavity mirrors, 40 Watt power output was easily obtained for the transverse flow mixing discharge CO2 laser. It was found that the active length had exceeded 20mm and the gain was high. The successful demonstration of HCl laser validated feasibility of realization HBr laser. Pump reaction system of HBr laser was selected.Through the experimental investigation of these representative bands, it is confirmed that overtone HF, HBr, DCl laser all could be realized on a single chemical laser device driven by high voltage discharge.