Optical design for laser tweezers Raman spectroscopy setups for increased sensitivity and flexible spatial detection

TL;DR

This paper introduces a novel optical design for Laser Tweezers Raman Spectroscopy that doubles collection efficiency by capturing both forward and back-scattered light, enabling sensitive, flexible, and less invasive biological sample analysis.

Contribution

The authors present a method to simultaneously collect forward and back-scattered light in LTRS, enhancing sensitivity and spatial flexibility while reducing laser power and enabling polarization analysis.

Findings

Doubles collection efficiency in LTRS

Allows simultaneous confocal and non-confocal measurements

Enables longer monitoring of sensitive biological samples

Abstract

We demonstrate a method to double the collection efficiency in Laser Tweezers Raman Spectroscopy (LTRS) by collecting both the forward and back-scattered light in a single-shot multitrack measurement. Our method can collect signals at different sample volumes, granting both the pinpoint spatial selectivity of confocal Raman and the bulk sensitivity of non-confocal Raman simultaneously. Further, we display that our approach allows for reduced detector integration time and laser power. Thus, our method will enable the monitoring of biological samples sensitive to high intensities for longer times. Additionally, we demonstrate that by a simple modification, we can add polarization sensitivity and retrieve extra biochemical information.