Digital Volume Reflection Holography

Holography is the recording of the interference pattern of a reference and light reflected from or transmitted through an 3D object. In conventional digital holography, the interference intensity pattern is recorded on a digital camera. Recording reflection holograms using this device are usually not possible. In this paper, we outline a method to numerically convert digital transmission holograms to digital volume reflection holograms by simulating a reflection grating which incorporates a fast longitudinal variation along with information from the transmission hologram function. This longitudinal variation would from the interference of two counter-propagating waves, similar to what would be physically recorded in a bulk medium for a volume reflection grating. Coupled wave theory is then used to read the simulated volume reflection hologram and reconstruct the object. Wavelength multiplexing is readily achieved in this simulated volume hologram recording. Volume reflection holography has the advantage of excellent wavelength selectivity during readout using multispectral or white light. We demonstrate digital volume reflection holography by numerically simulating digital transmission hologram recording using simple objects such as Gaussian beams at two different wavelengths. This is followed by experimentally recording the digital transmission holograms of two objects with different wavelengths and repeating the reflection hologram conversion and readout numerically. Digital volume reflection holography is expected to have applications in 3D color holographic displays.