Experimental Research And Theoretic Analysis On Time-synchronized Dual-wavelength Transversely Excited Atmospheric Pressure CO₂ Laser

The Transversely Excited Atmospheric pressure (TEA) CO₂ laser has been widely applied in multi-photon excitation and isotope separation. The experiments proved that the double-frequency TEA CO₂ laser far exceeded its single-frequency counterpart. This paper presents a new type of dual-wavelength TEA CO₂ laser with fine space-overlap and time-synchronization, and its output lines can be adjusted via turning the gratings. The experimental setup and the theoretic analysis of such new kind of laser are shown in this thesis, and its capabilities also be tested by the data of experiments.At the first, this thesis reveals the experimental setup of the dual-wavelength TEA CO₂ laser. It is formed by two gratings, and a germanium plate, where one grating is in front of the other. The two resonant cavities make use of each other, thus, the dual-length lines can be exported by the coupling of the germanium mirror. The formation of the cavity is simple, and the tuning can be convenient. The changing of the effective acreage of the two gratings will influence the space-overlap of the output spots. The space overlap of spots can be improved via tuning the acreage of the gratings in certain range. The ratio of the effective acreage of the spots also affects the ratio of the two laser pulses. In general, the corresponding line of the grating with bigger effective acreage is stronger than others. The effective acreages of two gratings are adjusted to keep the energy proportion of two lines under the 1:1. The detuning of the angle of the two gratins greatly influences and improves the time synchronization of the two pulses. The time interval of the two output pulses decreases from 1000ns to 400ns via adjusting the angle of the gratings.Then some improvements which bestow the cavity with certain characteristics are achieved on the basis of the original laser. There are more adjustment factors, such as the detuning of gratings and the length of the cavity. The resonance cavity can make use of each other better, and the synchronization of the dual-wavelength laser can be improved. The experiment indicates that the time interval of laser with such cavity can be decreased, and the least can be 200ns. In the light of the experimental data, the characteristics of the laser are analyzed. The factors which influence the time overlap and time synchronization also are focused in this thesis.The function rules of dual-wavelengths are revealed at the end of the thesis. The time of the peak value of the gain occurs can be got via solving the coupled pair of the rate equation and the intension equation; the output time delay can also be obtained from the time of the gain occurs' difference of two pulses. In the condition of detuning, the loss of the resonant cavity is analyzed...