Measurement of complex ?(3) using degenerate four-wave mixing with an imaged 2-D phase grating

Abstract

We present a simple optical arrangement for phase sensitive detection of degenerate four-wave mixing (DFWM) to characterize the real and imaginary parts of Chi((3)) using an imaged 2-D phase grating. Phase sensitive coherent detection of DFWM signal is demonstrated. Phase stabilization of the interferometric arms is obtained passively with the 2-D grating. A processable polyacetylene sample is characterized at a wavelength of 1.5 microm using this technique. The observed nonlinearity is determined to be a fast (<250 fs) effect using a simple test.

Thick Optical‐Quality Films of Substituted Polyacetylenes with Large, Ultrafast Third‐Order Nonlinearities and Application to Image Correlation

“…The DOE assures the spatial and temporal overlap of the fs pulses in the nonlinear medium. For a detailed description, see Tseng et al [43]. After the DOE, the diffracted beams are collimated into a forward-folded crossed-beam phase-matched (BOXCARS) geometry so that parallel-propagating beams pass through the 2D transmission binary masks.…”

Compact and self-aligned all-optical image correlator based on third-harmonic generation

“…In this compact optical correlator, the input beam is focused to a spot on the DOE beam splitter, which splits the input beam into four ͑±1 , ± 1͒-order beams. The DOE is similar to the 2D phase grating with 40 m periods in both directions used in [6], which is designed to optimize the diffraction efficiency into the ͑±1 , ± 1͒ orders at 1550 nm for coherent detection of the degenerate four-wave mixing (DFWM) signal in a folded crossed-beam phase-matched coherent anti-Skokes Raman spectroscopy (BOXCARS) geometry [7]. Due to fabrication imperfections, the DOE dif-fracts 10% of the input energy into each of the ͑±1 , ± 1͒-order beams.…”

“…An attractive alternative to beam steering optics is to use diffractive optical element (DOE) beam splitters. It has been demonstrated by several groups that relatively simple and easy to align setups can be built for various transient grating [4,5] and fourwave mixing [6] experiments utilizing subpicosecond pulses with DOE beam splitters. These systems generally require fewer optical elements than their counterparts using beam steering optics.…”

Third-harmonic generation and its applications in optical image processing

“…The DOE is a 2D phase grating with 40 mm periods in both directions and designed to optimize the diffraction efficiency into the (AE1, AE1) orders at 1550 nm. 31 The input beam is focused to a spot on the DOE and diffracts into four (AE1, AE1) order beams in a folded crossed-beam phase-matched coherent anti-Skokes Raman spectroscopy (BOXCARS) geometry, as shown in Fig. 6.…”