Cascaded second-order nonlinearity for ultrashort pulses control and characterization

Crystals with second-order nonlinearity are commonly used for wavelength conversion. Cascaded second-order nonlinearity, which involves placing two nonlinear crystals in sequence, provides wavelength conversion over a more flexible range.

In this paper, two different applications of cascaded second-order nonlinearity are established. First, a novel ultrashort pulses diagnostic technique, Cascaded nonlinearity inside a spectrometer (CaNIS), is proposed, demonstrated experimentally and verified by simulation. Second, a new remote spectroscopy laser system using passive negative feedback, and three cascaded second-order nonlinear crystals is proposed. The cascaded nonlinearity is used to create a broad spectrum which is essential for the ability to temporally focus the pulse beyond 10km. This laser is expected to deliver 100mJ, 1ps, UV pulses.