Study On Same Space Dual-wavelength Tunable TEA CO₂ Laser

In this paper, the development process of CO₂ laser is reviewed, particularly the study background and actuality of TEA CO₂ laser. The application of CO₂ laser in industry processing, medical treatment, wireless optical communication and isotope separation is introduced briefly. Especially in order to increase the selectivity of isotope seperation, multiphoton dissociation boron isotope using infrared ray need dual-wavelength laser pulse overlaped in space and time. We analyse many schemes of obtaining dual-wavelength laser pulse, then develope a new kind of same space dual-wavelength tuable TEA CO₂ laser which is formed by two grating-plane cavities overlapped in the space. One grating is placed in front of the other along the cavity axis overlapping in the space. The two cavities utilize each other and produce dual-wavelength laser pulse. In a laser pulse, the two optical fields overlap partially in the space.A mathematics model which describes the optical field in the new TEA CO₂ laser cavity is established acording to the diffraction integral equation of laser cavity. The laser cavity can be regarded as one demension Gauss cavity in the upright direction and one complicated cavity in the level direction. The optical field distribution in the level direction is computed .The calculation result indicates thatthe optical field overlapping in the level direction associates with not only the wavelength difference but also the area of grating used efficently.The smaller the difference of two wavelength is ,the better the overlapping in space is.The bigger the aera of grating used efficently which closes to the discharged room is, the better the overlapping in space is. At same time, every branch' s energy also changes. The energy in a laser pulse is estimated 3.5J on light of the exhaust of laser cavity which is caculated out in advance.The overlapping of two optical field in space, the energy adjusting, the branch tuning, the time characteristic of laser pulse and the spread characteristic of optical field are all studied in experiment. The experiment result is consistent with theoretical analysis basically.We have finished the experiment of multiphoton dissociation Bcl3 using the two branches R(34) and R(36) of the new kind of TEA CO₂ laser. A better effect-has been achieved that concentrated coefficient is 1.8.