Design And Research Of Annular Waveguide Random Laser

The conception of random laser was putted forward on the luminescencemechanism of stimulated emission of radiation. As a new type of micro-cavitylaser, its unique light emission principle and light transporting properties make itmore and more popular in optics. The optical resonator is replaced by multiplescattering, which provide a feedback similar to cavity resonator, and increasedthe walking distance of the light. When the gain is introduced, it can lead tostimulated radiation, and then produce the laser. The annular cavity randomlydistributed in the medium, different cavities have different location, frequency,and so the light emitting direction. Therefore, random lasers have a laser outputin each direction, the spectral structures are different with the viewing anglechange. Also, the number of random laser spectral patterns also differentbecause of different random medium volume, pump area, etc.On account of the difference between the two type lasers, how to combinethe difference is especially popular in random laser research.Based on the light emission properties of random medium and light transportingproperties of waveguide, the paper designs and optimizes the waveguide random laser,to make the random laser similar to conventional laser that can emitunidirectional, monochromatic, high intensity laser beam. The main contents ofthis thesis are as follows:First, the basic characteristics of the random laser are analyzed, such as criticalarea, threshold, direction. Then point out the problem of the random laserresearch field.Next, based on emission principle, we put forward the theory research methodand numerical simulations and the designing basis, then analyze the electromagnetismproperty of linearity waveguide.Finally, the paper put forward a new type of waveguide random scatteringsystem, which is the combination of random medium and annular waveguide, the finite difference time domain (FDTD) method for numerical calculation is utilized.While the non-waveguide structure, without scattering particles in certain regions andother structures, as compared structures also have numerical calculation in the samesimulation parameters. The results show that, the design of the annular waveguiderandom lasers achieve a good result of high degree of concentration and minoritynumber of patterns of the emitted laser light, which is the general random laser can notbe achieved.