Wide-field Surface-Enhanced Coherent Anti-Stokes Raman Scattering Microscopy

Abstract

Surface-enhanced Raman scattering (SERS) spectroscopy has been used extensively to study biology, chemistry, and materials. However, a point-by-point SERS mapping is time-consuming, taking minutes to hours for large-scale imaging. Here, we report a wide-field surface-enhanced coherent anti-Stokes Raman scattering (WISE-CARS) microscopy for monitoring nanotags in live cells and label-free detection of metabolic molecules. The WISE-CARS microscope achieves an imaging speed as fast as 120 frames per second for a large field of view of 130 microns X 130 microns. By spectral focusing of femtosecond lasers, a hyperspectral WISE-CARS stack of 120 frames can be acquired with a spectral resolution of 10 cm-1, where over 1 million Raman spectra are parallelly recorded within 0.5 seconds. As applications, we demonstrate time-lapse, 3D WISE-CARS imaging of nanotags in live cells as well as label-free detection of adenine released from S. aureus.