Wavelength-Coded Holographic Microscopy:
A wavelength-coded multifocal microscope incorporates multiplexed and wavelength-coded holographic gratings to generate wavelength-selective multifocal planes. 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. Figure on the left shows Two depth-resolved images of an onion obtained with wavelength-coded multifocal microscopy using both blue and red LEDs for illumination. Figure in the middle shows One of the two depth-resolved images obtained with wavelength-coded multifocal microscopy when the blue LED is on and red one is off.
Figure on the right shows One of the two depth-resolved images obtained with wavelength-coded multifocal microscopy when the red LED is on and blue one is off.