Laser utilizing a raman active material for double quantum absorption

摘要

1,101,017. Lasers. HUGHES AIRCRAFT CO. 1 Aug., 1966 [13 Aug., 1965], No. 34443/66. Heading H1C. A laser active medium consists of potassium caesium or rubidium vapour which is double quantum pumped to produce saturation of the absorption transition by incident radiation at each of two frequencies W L , W s , the resonant double quantum pumping being effected by a pumping laser which operates in association with a Raman active material, and the two pumping frequencies being such that the energy level separation #E of the active medium is equal to hW L +hW s . As shown in Fig. 2, pumping radiation of frequency W L is generated by a tuned giant-pulse ruby or neodymium laser 31 which interacts with a Raman active material 35 contained in a cell 37 to produce stimulated Raman emission 39 of lower frequency W s in addition to propagating the laser radiation 33. For pumping a potassium vapour laser, the Stokes emission W S from the Raman cell raises the level of energy from the ground state to the 4pSP3/SP/ 2 intermediate level, while the absorption transition from the intermediate level to the 68¢ level is completed by the pumping laser emission W L , Fig. 3 (not shown). Emission of the required frequency W L from a ruby laser is obtained at an operating temperature of about- 40‹ C., and a suitable Raman material for emitting frequency W S may be 1-Bromonaphthalene. Other suitable Raman materials are described. The pumped vapour laser is sufficiently tuned by using the reflectivity of the end windows and emits radiation in the infra red.