A multimodal laser-scanning nonlinear optical microscope with a rapid broadband Fourier-transform coherent Raman modality

TL;DR

This paper introduces a multimodal nonlinear optical microscope that combines broadband coherent Raman spectroscopy with other nonlinear imaging techniques, enabling rapid, high-resolution, chemical-specific imaging of samples.

Contribution

It presents a novel integrated system using a single ultrafast laser source for broadband coherent Raman spectra and other nonlinear modalities on the same microscope.

Findings

Broadband coherent Raman spectra (>1000 cm-1) with high spectral resolution (<5 cm-1)

Rapid spectral acquisition rate (3-12 kHz)

Raman hyperspectral imaging at >11 frames per second

Abstract

Nonlinear optical microscopy allows rapid high-resolution microscopy with image contrast generated from intrinsic properties of the sample. Established modalities such as multiphoton excited fluorescence and second/third-harmonic generation can be combined with other nonlinear techniques, such as coherent Raman spectroscopy which typically allow chemical imaging of a single resonant vibrational mode of a sample. Here, we utilize a single ultrafast laser source to obtain broadband coherent Raman spectra on a microscope, together with other nonlinear microscopy approaches on the same instrument. We demonstrate that the coherent Raman modality allows broadband measurement (>1000 cm-1), with high spectral resolution (<5 cm-1), with a rapid spectral acquisition rate (3-12 kHz). This enables Raman hyperspectral imaging of > kilo-pixel images at >11 frames per second.