Polarization-based idler elimination: enhancing the efficiency of optical parametric amplification.

This study presents a novel way to increase the energy conversion efficiency of optical parametric amplification by eliminating the idler wave from the interaction using consecutive type-I and type-II amplification processes. By using the aforementioned straightforward approach the wavelength tunable narrow-bandwidth amplification with exceptionally high 40% peak pump-to-signal conversion efficiency and 68% peak pump depletion was achieved in the short-pulse regime, while preserving the beam quality factor of less than 1.4. The same optical layout can also serve as an enhanced idler amplification scheme.

Interferometric measurements of nonlinear refractive index in the infrared spectral range.

This study presents the development and application of interferometric technique for the measurement of nonlinear refractive index of optical materials, while directly accounting for experimentally determined laser pulse shape and beam profile. The method was employed in a systematic study of nonlinear refractive index on a series of common optical materials used in near and mid-IR spectral range, where experimental data on nonlinear material properties is still scarce. The values of nonlinear refractive index were determined at 1.03 µm, 2.2 µm, and 3.2 µm. The measurement results are compared to the values determined by previous studies (where available), and the influence of cascaded second-order nonlinearities is discussed.