Compact source of energetic sub-nanosecond red pulses based on cascaded quasi-phase-matching in aperiodically poled lithium niobate.

We present a simple, compact source of sub-nanosecond pulsed red radiation, based on cascaded nonlinear optical processes-degenerate optical parametric generation and sum-frequency generation-performed with a sample of aperiodically poled lithium niobate pumped by passively Q-switched 1.064 µm Nd:YAG laser. This system does not require feedback from an optical cavity; a single pass of the short pump is all that is required to obtain the cascaded processes, which shortens the output pulse.

Switchable phase/intensity sensor made with ring-shaped and hexagonal ferroelectric domains.

We present a device, similar to a Shack-Hartmann sensor, that can detect both the intensity distribution and wavefront of an incident wave. Its operation is based on the use of an array of electrically controllable Fresnel zone plates made in a ferroelectric crystal, lithium niobate. This sensor, which requires only one camera, can be quickly switched between intensity- and phase-detecting modes.