Single acquisition reconstruction of nonlinear susceptibility and Raman tensors at the diffraction limit

TL;DR

This paper introduces a novel microscopy method that combines Raman spectroscopy and SHG to determine nonlinear optical tensors at the diffraction limit using a Bessel-Gaussian laser beam.

Contribution

It presents a new approach to measure nonlinear optical tensors by exploiting spatial and temporal offsets of a specialized laser beam.

Findings

Combined Raman and SHG techniques provide comprehensive material insights.

The proposed method enables tensor determination at the diffraction limit.

Utilizes a Bessel-Gaussian laser beam for spatial and temporal offset measurements.

Abstract

Raman spectroscopy and Second Harmonic Generation (SHG) are complementary, non-destructive techniques that provide rich and distinct insights into the structural and electronic properties of materials. Raman spectroscopy offers detailed information on vibrational modes, phase transitions, temperature, and local stress, while SHG is highly sensitive to symmetry and orientation, particularly in non-centrosymmetric structures. In this work, in addition to combining both techniques, we propose a novel approach to determine the nonlinear optical tensor, leveraging the spatial and ultra-fast temporal offset of a Bessel-Gaussian laser beam at the microscope's focal point.