New phenomena related to pulsed far-infrared superradiant and Raman emission

摘要

In order to produce ultrashort far-infrared (FIR) laser pulses we have investigated the superradiance and Raman emission of various molecular transitions optically pumped with the pulses of 10 $mu@m-hybrid- or high-pressure single-mode-CO$-2$/ lasers truncated within 10 ps. Furthermore we have truncated directly the FIR laser pulses with the first FIR plasma shutter. In our experiments we have observed new phenomena which include e.g. new interrelations between superradiance, swept-gain superradiance and Raman emission, anticorrelated fluctuations of pump radiation versus FIR emission, first optical free induction decay of 10 $mu@m-CO$-2$/-laser pulses with FIR emitting molecular gases. Finally, we have proved the first spontaneous infrared solitons in stimulated far-infrared Raman scattering on NH$-3$/. We have observed solitons in the depletion region of the infrared pump radiation with corresponding dark solitons in the Stokes pulses and detected the laser phase change connected with the soliton generation.