Analysis and experimental assessment of the sensitivity of stimulated Raman scattering microscopy

Kiichi Fukui,Fumihiro Dake,Shin'Ichiro Kajiyama,Kazuyoshi Itoh,Yasuyuki Ozeki

doi:10.1364/oe.17.003651

Abstract

We theoretically show that the shot-noise-limited sensitivity of stimulated Raman scattering (SRS) microscopy, which enables high-contrast vibrational imaging, is similar to that of coherent anti-Stokes Raman scattering microscopy. We experimentally confirm that the sensitivity of our SRS microscope is lower than the shot-noise limit only by <15 dB, which indicates that the high-sensitivity of SRS microscopy is readily available.

Highlights

Coherent nonlinear-optical microscopy techniques [1,2,3,4,5], which exploit nonlinear-optical interactions induced by tightly focused laser pulses, have provided a way to threedimensionally visualize unstained biological samples
It is crucial to suppress so-called nonresonant signals emitted from solvent, which significantly reduce the contrast of resonant coherent anti-Stokes Raman scattering (CARS) signals of interest
We present a detailed analysis on the sensitivity of Stimulated Raman scattering (SRS) microscopy, and experimentally demonstrate that the sensitivity of our SRS microscope is lower than the theoretical limit only by

Summary

Introduction

Coherent nonlinear-optical microscopy techniques [1,2,3,4,5], which exploit nonlinear-optical interactions induced by tightly focused laser pulses, have provided a way to threedimensionally visualize unstained biological samples. SRS reflects only vibrational resonances and is unsusceptible to nonresonant nonlinearities, providing us with high vibrational contrast Taking advantage of this fact, the application of SRS to vibrational microscopy has been recently reported by several groups [13,14,15,16]. We pointed out in Ref. 15 that the shot-noise-limited sensitivity of SRS microscopy is comparable to that of CARS microscopy because SRS can be viewed as the homodyne detection of the nonlinear-optical signal with the excitation pulse. This prediction would further enhance the merit of SRS microscopy, its actual sensitivity has yet to be investigated. We present results of live-cell imaging with SRS microscopy

Theory of SRS microscopy

Experiment

Summary