The Study Of Lasing Without Inversion In An Open V-Type System

The study of lasing without inversion (LWI) is an important and active research front field in international lasing physics nowadays. The study of LWI has not only an important theoretical value, but also wide application prospects. As a new mechanism of producing laser, LWI can produce laser in the fields that it is very difficult even impossible to get laser (x or even r spectrum) using the traditional methods. So nowadays it has attracted the interest of a lot of people.Based on the work of the former people, in this paper, we mainly studied the effect of the driving field phase fluctuation, the effect of Gaussian transverse profile of the driving and laser fields, the Doppler effect and so on for the open V-type LWI system. This paper consists of four chapters.In Chapter 1, we explained the significance for studying LWI and the basic principle of producing LWI, introduced simply the current research state and the main contents for the important study subject at present.In Chapter 2, we analyzed the effect of the driving field phase fluctuation on the gain and dispersion and population differences in an open V-type three-level non-inversion lasing system and then discussed the effects of the incoherent pumping rate, the ratio of the atomic injection rates, the atomic exit rate, the Rabi frequency of the probe and driving fields and their corresponding detuning on the gain, dispersion and population differences of the system, and got some important conclusions different from those in closed or other open systems.In Chapter 3, we studied the effect of Gaussian transverse profile for the driving and laser fields on lasing without population inversion (LWI) in a closed V-type system and an open V-type system. Moreover, we discussed also the effect of the unsaturated gain coefficient, the cavity-damping rate, the ratio of the atomic injection rates and atomic exit rate on the corresponding systems.In Chapter 4, we mainly discussed the effect of Doppler broadening on the gain, dispersion and the frequency up-conversion of the open V-type LWI system and compared the differences and the same between the open system and the corresponding closed system. Then got some new conclusions. First, When consider the Doppler effect of the fields, through choosing appropriate test condition we may get the proper Doppler width and the best gain of the system. Second, only with the proper up-conversion ratio can we get the up-conversion as well as enough LWI gain. Third, as for the open system, the smaller the injection ratio and the detuning the better the gain is. Finally, because of the Doppler effect, when the driving and the probe fields are counterpropagating, the gain is surging in a certain area of the detuning of the probe field and the extent of the surging is corresponding to the Doppler width.