High-resolution optical coherence microscopy for high-speed, in vivo cellular imaging

Optical coherence microscopy (OCM) is demonstrated with a high-speed, broadband, reflective-grating phase modulator and a femtosecond $\mathrm{Ti}:{\mathrm{Al}}_2{\mathrm{O}}_3$ laser. The novel system design permits high-resolution OCM imaging in a new operating regime in which a short coherence gate is used to relax the requirement for high-numerical-aperture confocal axial sectioning. In vivo cellular imaging is demonstrated in the Xenopus laevis tadpole and in human skin with a $3‐\mathit{\mu }\mathrm{m}$ coherence gate and a $30‐\mathit{\mu }\mathrm{m}$ confocal gate. The ability to achieve cellular imaging with a lower numerical aperture should facilitate the development of miniaturized probes for in vivo imaging applications.