Eliminating the broadening by finite aperture in Brillouin spectroscopy

TL;DR

This paper introduces an innovative optical setup for Brillouin spectroscopy that eliminates broadening caused by finite aperture effects, enabling larger collection angles and improved measurement accuracy.

Contribution

A novel optical arrangement that collects all scattered rays at the same angle onto a single pixel, enhancing luminosity without sacrificing spectral resolution.

Findings

Effective reduction of aperture broadening demonstrated

Increased collection angles improve signal strength

Experimental validation confirms device efficiency

Abstract

We present a new optical arrangement which allows to avoid the broadening by finite aperture in Brillouin spectroscopy. In this system, all the rays scattered at the same angle by the whole scattering volume are collected on a single pixel of the area detector. This allows to use large collection angles, increasing the luminosity without lowering the accuracy of the frequency-shift and linewidth measurements. Several results of experimental checks are provided, showing the efficiency of the device.