Experimental Study Of Tunable Tea CO₂ Laser With Intelligent Control

In recent years, air quality has been received wide attention. CO2 laser differential absorption lidar(DIAL) with high sensitivity and range of action has become an important technology in the air environment detection. The CO2 laser is the critical component of a DIAL instrument, and its spectral wavelength is at the mid infrared region of 9~11μm. The wide range of the region not only contains the absorption spectra of most gaseous pollutants, but also provides the basis for the laser tuning.With the improvement of the production technology of laser, the intelligent control has become the inevitable trend of its development, this control method is more stable and reliable, which is suitable for long time work.In order to study the laser for differential absorption radar, after analyzing the progress of domestic and abroad, the experimental study of the TEA CO2 laser and its control system has been carried out.In this dissertation, based on the theory of TEA CO2 laser, the control structure of the direct drive grating has been used to complete the spectral line selection of the TEA CO2 laser. The servo system is driven by the driver module and controlled by ARM. The servo closed-loop control system is debugged. To make the servo motion control more stable, the servo closed-loop control system is debugged. the software is programmed to test servo system location stability, and the results show that the stability can be over 99%. The hardware structure of the control system is designed,and the software of the laser control is designed by combining the CVM programming and the functional requirements of the driver. The electromagnetic compatibility(EMC)analysis and design of the laser are targeted for the EMC of the laser with strong interference. The final design system can automatically adjust the high pressure and complete the precise selection according to the input line, and control state of laser,such as the gas breathing of the laser, the system error and so on.The rapid tuning of single and double laser has been studied. Under 15 k V high pressure, 81 non limiting spectral lines(the maximum output energy among them is485.7m J) and 73 limiting spectral lines under the aperture of 10 mm were obtained. The designed laser energy floating range is less than 2%, and the spectral lines can becompletely reproducible. Laser pulse pair with two random wavelengths can trigger the laser to obtain output more than 100 ms. The tuned output of two random wavelength spectral lines can be obtained by a single laser within more than 100 ms.The double cavity laser can complete the rapid tuned output of two random wavelength spectral lines with arbitrary time interval. Its performance meets the application of DIAL completely.