Holobricks: modular coarse integral holographic displays.

Here, we propose and demonstrate a modular holographic display system that allows seamless spatial tiling of multiple coarse integral holographic (CIH) displays called "holobricks". A holobrick is a self-contained CIH module enclosing a spatial light modulator (SLM), a scanner, and periscopic coarse integral optics. Modular CIH uses a coarse pitch and small area but high-bandwidth SLM in conjunction with periscopic coarse integral optics to form the angularly tiled 3D holograms with large viewing areas and fields of view. The creation of periscopic coarse integral optics prevents the optical system from being larger than the holographic image and allows the holographic fringe pattern to fill the entire face of the holobrick. Thus, multiple holobricks can be seamlessly abutted to form a scalable spatially tiled holographic image display capable of both wide field-of-view angle and arbitrary large-size area. We demonstrate an initial prototype that seamlessly tiles two holobricks each with 1024 × 768 pixels, 40° FOV, full color, 24 fps, displaying 2D, 3D holographic stereograms, and full parallax 3D CGI Fresnel holograms.

Scalable coarse integral holographic video display with integrated spatial image tiling.

The dynamic Coarse Integral Holography (CIH) display demonstrated previously can scan the low space bandwidth product (SBP) holographic images delivered by a high bandwidth spatial light modulator (SLM) to form a hologram array for angular tiling of the 3D images for a large field-of-view but only a modest size despite the utilization of the full bandwidth of the SLM in use. In this paper, we propose a scalable approach using seamless spatial tiling of the full bandwidth images generated by two high bandwidth SLMs using a resonant scanner and a high performance galvanometric scanner for a scalable CIH display capable of achieving twice of the final image size and doubled horizontal field-of-view (FOV). A proof-of-concept system is demonstrated with integrated full-parallax holographic 3D images. The proposed method has the potential to tile images generated by more than two SLMs for scalable large size and wide FOV holographic displays.

Full bandwidth dynamic coarse integral holographic displays with large field of view using a large resonant scanner and a galvanometer scanner.

An efficient method to implement the coarse integral holographic (CIH) concept for dynamic CIH displays is to scan the information generated from a spatial light modulator (SLM) of a low space bandwidth product (SBP) but high bandwidth to form the hologram array for the integral optics. Previously, just over half of the SLMs bandwidth was utilized due to the fact that the galvanometer scanner in use could not tile all the holograms that the SLM is capable to produce, resulting in the loss of nearly half of the field of view (FOV). Here, we propose a full bandwidth dynamic CIH display using a large resonant scanner in conjunction with a hybrid raster scanner, which can utilize the full bandwidth of the spatial light modulator and double the horizontal FOV. Experimental results confirm that with the SLM and scanners as used, the FOV can reach 48° when the SLM reaches its full bandwidth. This approach can be used for future scalable and tileable CIH display systems.

Coding/decoding two-dimensional images with orbital angular momentum of light.

We investigate encoding and decoding of two-dimensional information using the orbital angular momentum (OAM) of light. Spiral phase plates and phase-only spatial light modulators are used in encoding and decoding of OAM states, respectively. We show that off-axis points and spatial variables encoded with a given OAM state can be recovered through decoding with the corresponding complimentary OAM state.

Polarimetric imaging and blood vessel quantification.

We applied a polarimetric analysis to retinal imaging, to examine the potential improvement in characterizing blood vessels. To minimize the reflection artifact of the superficial wall of the blood vessel, we computed depolarized light images by removing the polarization retaining light reaching the instrument. These depolarized light images were compared to images from the average of all the light. Michelson contrast was computed for the vessel profiles across arteries and veins, and was higher for the depolarized light images. Depolarized light images provide one step towards improving the characterization of retinal blood vessels.

Unique features of optical scanning, single fiber endoscopy.

BACKGROUND AND OBJECTIVE: To advance the field of minimally invasive medical procedures, an ideal endoscope should provide high-resolution images with variable magnification from an ultra-thin package, while adding depth cues and integrating optical diagnoses and therapies. Satisfying all these requirements is extremely difficult using commercial endoscopes. A new imaging technology is introduced that uses directed laser illumination, which is scanned at the distal end of a flexible endoscope. STUDY DESIGN/MATERIALS AND METHODS: A single-mode optical fiber is driven in vibratory resonance using a piezoelectric actuator. The emitted laser light is scanned in two-dimensions over test specimens. Digital images are constructed by detecting optical power one pixel at a time. RESULTS: Unique features of the fiber scanning scope are rapidly changing magnification, enhanced topographic detail, and concurrent fluorescence imaging, which are demonstrated and discussed. CONCLUSION: This fiber scanning scope has the potential for pixel-accurate delivery of high quality laser radiation, allowing the future integration of imaging with diagnosis and therapy.