Fast Reflective Optic-Based Rotational Anisotropy Nonlinear Harmonic Generation Spectrometer

Rotational anisotropy second harmonic generation (RA-SHG) has emerged as effective probe of structural and electronic symmetry of hard condensed phase systems, as well as a spectrocsopic tool for investigating the energy-dependent nonlinear electronic properties of solids. A common implementation of this technique has involved sample rotation to obtain the maximal number of nonlinear susceptibility coefficients, leading to signficiant challenges in experimental alignment which have recently been overcome by diffractive optic-based approaches. However, the same diffractive optics that have opened up this metrology to a variety of new sample configurations have also restricted the RA-SHG spectrometer in both data acquisition speed and broadband spectroscopic capability. We describe the design and application of an RA-SHG spectrometer based almost entirely upon reflective optics that overcomes the wavelength-dependent shortcomings of current state of the art RA-SHG devices and provide examples of the apparatus' application to a variety of test samples.