Heterodyne detected transient grating spectroscopy in resonant and non-resonant systems using a simplified diffractive optics method

We report a simplified optical heterodyne detected transient grating setup consisting of a single diffractive optical element based on modifications of the arrangement used by Miller and co-workers [J. Phys. Chem. A, 103 (1999) 10619]. Our arrangement features ease of alignment, suppression of scattering and is free of pump–probe contamination in the detected transient grating signals. The capability of our arrangement is demonstrated by measurements on a non-resonant system, CS2, and a resonant system, malachite green in ethanol.