Laser medium of O_2(~1DELTA_g) dimer

摘要

The two bands of O_1(~1DELTA_g) dimer, whose peak wavelengths are 703 and 634 nm respectively, were first observed by Arnold et al. Then a lot of researches on the spectra of O_2(~1DELTA_g) dimer and the rate constant of reaction O_2+O_2＝O_4 were made by many researchers. A net gain of 2.8% cm~(-1) for O_2(~1DELTA_g) dimer at 703 nm was first obtained by Yoshida et al. So O_2(~1DELTA_g) dimer will possibly become a new laser medium. We have also made researches on O_2(~1DELTA_g) dimer systematically. In theory, the potential surfaces for O, dimer belonging to different structures were calculated by means of Gaussian-92 program. Results show that D_(2h) group is the existing structure of O_2 dimer, its lower level is a repulsive state formed by twoO_2 (~3∑_g~-)> and its upper level is a bound state-O_2(~1DELTA_g) dimer. Fig. 1 shows the curves of O_2 dimer belonging to D_(2h) group. In experiment, a system used for exciting high purity oxygen by microwave was established, and two new bands of O_2(~1DELTA_g) dimer, whose peak wavelengths are 486 and 656.4 nm, respectively, were observed, and small signal gain coefficients of 486 and 656.4 nm were obtained using the method of amplified spontaneous emission. At last, laser oscillation was realizedat 486 and 656.4 nm with flat-concave resonators for the first time.