Investigation of optical parametric oscillators with noncollinear interaction

An analysis is made of the self-interaction and of the processes governing the angular and frequency spectra of a single-resonator pulse optical parametric oscillator with a noncollinear interaction. It is shown that at high pump powers the structure of the excited oscillations and the widths of the angular and frequency spectra are all governed largely by the eigenmodes formed as a result of parametric amplification in pump beams. Theoretical and experimental investigations are reported of the characteristics of these modes and of their excitation conditions. An analysis is given of the special features of the formation of the angular and frequency spectra in a conventional single-resonator optical parametric oscillator and of the selection mechanisms specific to parametric oscillation in the case of nonresonant reflection of pump radiation and also when a dispersive resonator is used.