Optimization of sum frequency output from intra-cavity sum frequency generation in singly resonant optical parametric oscillator

Abstract Theoretical investigation and optimization of output characteristics of intra-cavity sum frequency generation between pump and the signal waves in singly resonant optical parametric oscillators (IC-SFG-SROs) are presented. Under the collimated Gaussian beam approximation, simple models considering different spatial orderings of SRO and SFG processes of IC-SFG-SROs are set up. The calculations based on experimental parameters are in good agreement with experimental results. Output characteristics of IC-SFG-SROs operated at other wavelengths are optimized and predicted. For given experimental conditions (pump wavelength, pump power and SRO crystal length), the optimum length of SFG crystal and SF power are calculated, respectively. Furthermore, when a periodically poled crystal with a cascaded pattern is used as the SRO crystal and SFG crystal, the optimum SFG crystal length and the SF power are also calculated. These calculations and models provide guidelines for designing and optimizing continuous-wave tunable IC-SFG-SROs.