Increasing the imaging depth of coherent anti-Stokes Raman scattering microscopy with a miniature microscope objective

Abstract

A miniature objective lens with a tip diameter of $1.3\mathrm{mm}$ was used for extending the penetration depth of coherent anti-Stokes Raman scattering (CARS) microscopy. Its axial and lateral focal widths were determined to be 11.4 and $0.86\mu \mathrm{m}$, respectively, by two-photon excitation fluorescence imaging of $200\mathrm{nm}$ beads at a $735\mathrm{nm}$ excitation wavelength. By inserting the lens tip into a soft gel sample, CARS images of $2\mu \mathrm{m}$ polystyrene beads $5\mathrm{mm}$ deep from the surface were acquired. The miniature objective was applied to CARS imaging of rat spinal cord white matter with a minimal requirement for surgery.

© 2007 Optical Society of America