Optimization And Design Of Acousto-optic Tunable Filters

The dissertation mainly has two components as follows:1. Optimization and design of acousto-optic tunable filters(AOTF)The AOTF is a kind of light dispersion device based on the the acousto-optic interaction principle. Optimization and design of AOTF have draw common concern of people. Keep to the point, works as follows are carried out. In chapter two, acoustic wave propagation in TeO₂ crystal is discussed in detail. Based on this, several problems are analyzed, such as momentum-matching condition in the angles of incidence, effects of optical rotation and birefraction on the design of AOTF, and so on. In chapter three, we have calculated the acoustic intensity distribution of different transducers, and found the sidelobe of AOTF can be reduced by changing the transducer geometry. A more excellent transducer geometry is proposed and its feasibility is analyzed and discussed.2. Research on Cerenkov second harmonic generation and parametric amplification in the Cerenkov-idler configurationAs we all know, the phase matching condition is critical in second harmonic generation in waveguides. In Cerenkov second harmonic generation (CSHG) scheme,the phase matching condition is satisfied automatically,but the conversion efficiency is low. If we introduce the aperiodic or periodic reversal of the nonlinear optical coefficient into the waveguides, the CSHG conversion efficiency can be improved greatly, the configuration also has been called quasi-phase matched CSHG (QPM-CSHG). Several research work in this filed has been carried out. In chapter four, the optimization of quasi-phase matched CSHG is demonstrated. Parametric amplification in the Cerenkov-idler configuration is modeled and analyzed theoretically. From the analysis, the conclusion can be drawed that the signal gain bandwidth is widened greatly in the parametric amplification in Cerenkov-idler configuration. In chapter five, the generation principle of THz-wave is introduced. The generation of THz-wave using Cerenkov-type difference frequency generation (DFG) is also discussed theoretically.