Df Laser Small Signal Gain Experimental Research

In accordance with the research and manufacture of high-energy chemical laser in our country, some technology work relating to CW FH/DF chemical laser have been done for the need of our laboratory's numerical simulation work. The major contents and conclusions are as following:The basic configuration and the working principle of burning-drive CW HF/DF chemical laser are presented in detail, the reaction model of DF chemical laser in the system of C2H4-NF3-He is given.The formulation of small signal coefficient is deduced, the significance and method of small signal coefficient measurement are introduced. Using the tunable semiconductor laser as probe light source, the enlarged light source by spreading lens can illuminate the whole area of the gain medium; the small signal coefficient's two-dimensional distribution in the flow-field's direction is measured by using the infrared camera as a detector. The small signal coefficient's contour lines of P1(11), P2(8) and P2(9) spectrum are presented, and we conclude that the P2(9)'s small signal coefficient is higher than that of P1(11) and P2(8). For each piece of spectrum, the gain appeared mainly in the middle of flow-field, and the highest gain coefficient appears in the point with a distance of 1cm~2cm away from the nozzle's face. Because of the low pressure, low temperature and high flowing voltage in the middle of the flow-field, the thermal energy that is out of use can be scattered and discharged timely, the gain appears mainly in the field. The experimental result in agreement with the reference's result and the theoretical simulation.The DC-charge-drive CW DF laser's basic configuration and working principle are introduced. The relation between the laser's output power and the mass flow of the raw material gases(SF6, D2 and 62) is measured. When the flowing voltage of SF6 is low, the laser's output power increases in accordance with the increase of SF6's flowing voltage; when the flowing voltage increase so high thatSF6's saturation effect appears, the output power decreases with the increase of SF6'sflowing voltage, moreover, the discharge process may stop. The reasons are as following: when the voltage is low, SF6 is in the absolutely ionized state, the increase of the flowing voltage causes the increase of SF6 in the discharge tube, so the temperature decreases, this effect causes the ionized SF6 and F's compensation decrease, the relating response have an effect on the decrease of the output power. The relation between the laser's output power and the flowing voltage of the raw material D2 is just the same as the above. The D2 increases the activation energy of DF and gives a disturbance to the gas-drive, so the output power decreases as the D2's flowing voltage increases. We also find that putting the O2 in the discharge tube can increase the laser's output power. The reaction between O2 and SFe can increase the F2's compensation, and the reaction between O2 and S can also decreases the aggradation of S.In the research on the flat-concave cavity of burning-drive CW DF laser, the single-line operation is achieved by the method of choosing one piece of spectrum using blazed grating. Fourteen lines of spectrum is recognized.