Wavelength-coded multifocal microscopy.

A wavelength-coded multifocal microscope incorporating multiplexed and wavelength-coded holographic gratings to generate wavelength-selective multifocal planes is presented. The focal planes are longitudinally spaced on the object plane, and each focal plane is probed by a designated wavelength. The recording of the multiplexed gratings takes place at a single wavelength by utilizing the Bragg degeneracy property; thus the maximum sensitive wavelength of blue 488 nm is used for recording, but the device is operated at a broad wavelength band of interest, all the way to red 633 nm. We present the design, implementation, and experimental image data demonstrating this microscope's ability to obtain biological tissue structures simultaneously at different focal planes using broadband illumination by LEDs.