| Summary: | 碩士 === 國立成功大學 === 光電科學與工程學系 === 100 === In this thesis, the dynamical behavior of the pump-modulation Nd:YAG and Nd:YVO4 lasers was studied under different harmonic modulations﹒Two methods associated with the average frequency difference and Correlation between Probabilities of Recurrence (CPR) were used to explore the phase synchronization between the laser output and modulation signal﹒The numerical simulations will compare with the experimental results﹒
When the modulation frequency approached to the relaxation oscillation frequency, F, the laser would be chaotic as the modulatin depth being greater than the threshold value﹒In this chaotic region, the capacibility of the phase synchronization for the region of the modulation frequency being less than the resonance frequency was worse than that for the region of the modulation frequency being greater than the resonance frequency﹒The behavior may be induced by that the lower and higher modulation frequency compared to the resonance have an initial phase difference in a general modulation harmonic system﹒Moreover, in the sub-harmonic(1/2 F) and the second harmonic(2F) modulations, the relaxtion oscillation frequency dominated the average frequency of the laser output, i.e., the average laser frequencies were near F﹒Since the analysis of the CPR, the sudden boundary agreed with the boundary of the threshold of the chaotic behavior﹒
In addition, the Nd:YAG laser was modulated by the simulation of the Lorenz chaotic signal﹒With the modulation frequency changed, gradations appeared on the method of the average frequency difference, because the change of the output frequency was smaller than that of the modulation frequency﹒The analysis of the CPR indicated that there was excellent phase synchronization near the resonance frequency in the low modulation depth.
|
|---|
