Broadly tunable quantum-enhanced Raman microscopy for advancing bioimaging

TL;DR

This paper introduces a quantum-enhanced Raman microscopy technique using amplitude-squeezed light, significantly improving sensitivity and SNR in bioimaging by overcoming classical shot noise limits.

Contribution

It demonstrates the first use of amplitude-squeezed light in tunable SRS microscopy for biological tissue imaging, achieving record noise suppression and SNR enhancement.

Findings

Achieved 5.2 dB amplitude squeezing of the Stokes beam.

Realized 3.6 dB noise suppression in biological imaging.

Enhanced SNR by 51% in quantum Raman microscopy.

Abstract

Stimulated Raman scattering (SRS) microscopy has emerged as a powerful technique for probing the spatiotemporal dynamics of molecular bonds with exceptional sensitivity, resolution, and speed. However, classically, its performance remains fundamentally constrained by optical shot noise, which imposes a strict limit on detection sensitivity and speed. Here, we demonstrate a quantum-enhanced SRS microscopy platform that circumvents this barrier by harnessing amplitude-squeezed light. Specifically, we generate a Stokes beam with $5.2~\mathrm{dB}$ of amplitude squeezing using traveling-wave optical parametric amplification in second-order nonlinear waveguides, and combine it with a tunable coherent pump to access vibrational modes spanning from $1000$ to $3100~\mathrm{cm}^{-1}$. Applied to quantum imaging of metabolites in biological tissue (pork muscle), our quantum-enhanced Raman microscope achieves an average noise suppression of $3.6~\mathrm{dB}$ and a $51\%$ enhancement in signal-to-noise ratio (SNR) -- to the best of our knowledge, the largest improvement reported to date in quantum-enhanced SRS microscopy of biological samples.