# Multi-channel lock-in based differential front-end for broadband Raman spectroscopy

## TL;DR

This paper introduces a low-noise, multi-channel acquisition system for broadband Raman spectroscopy that effectively compensates laser fluctuations, achieving high sensitivity close to the shot noise limit using lock-in detection.

## Contribution

It presents a novel multi-channel front-end design with pseudo-differential structure and lock-in technique to improve sensitivity in broadband Raman spectroscopy.

## Key findings

- Achieves sensitivity better than 10 ppm
- Effectively compensates laser intensity fluctuations
- Reduces electronic noise in the measurement

## Abstract

In Broadband Stimulated Raman Spectroscopy, the intrinsic limit given by the laser shot noise is seldom reached due to the electronic noise of the front-end amplifier and the intensity fluctuations of the laser source. In this paper we present a low-noise multi-channel acquisition system, with an integration-oriented design, able to compensate the common-mode fluctuations of the laser output power with the pseudo-differential structure and reach a sensitivity better than 10 ppm thanks to the lock-in technique.