Study On Theory And Applications Of Self-Mixing Interference Effects In LD Pumped Multi-Mode Solid-State Lasers

Self-mixing interference (SMI) is the effect that a portion of the output light of lasers is reflected or scattered by a moving target. The reflected light which contains information of the target is introduced into the cavity and causes variations in output power of the laser. Because this effect shows a resemblance to two beam interference, it is called self-mixing interference. Formerly, man always tried to avoid this effect, gradually man began to use this effect to measure some physical elements, and thus a new measuring technique appears. Recently, this effect drew more and more interests of people, it improved conventional interference system for its compact and simple structure and it is easily to be collimated. Though studies on self-mixing interference effect started in 1960s, works on this field in China have just begun.Firstly, this dissertation looked back to the whole process of self-mixing interference, from discovery to its applications. And introduced some representative groups in the world and their studying headings on this field. Analyzed the study purport and applying foreground of self-mixing interference.Secondly, based on LD pumped Nd:YVO4 and intra-cavity KTP frequency doubled green laser, this dissertation established experimental setup of this effect. Most studies on this effect used gas(CO2,He-Ne) lasers and semiconductor lasers respectively. We used LDP laser-the hotspot of lasers in our experiment. The experiment showed satisfying results compared to reported results. Thirdly, based on compound cavity laser model and the theory of multi-modes competition, we built a general model of this system and the simulated results of self-mixing interference signals were coordinate with the experimental results. Introduced small disturbance theory in quantum mechanism into SMI effects, and put forward the idea of replacing the light source of LED for the first time. By using FFT method on the signals, the measuring precision was highly improved.Lastly, we introduced some newest studies on this field and put forward some questions and developing trend of self-mixing interference effects.To sum up, this dissertation can be viewed as a fully introduction of self-mixing interference effects. And we can say that, with the development of the study, this effect can be used in many fields such as optical sensors, optical memory and chaos communications etc. And this is surly to be an important studying field.