Abstract: A method and system are disclosed for recording and displaying grazing-incidence (i.e., steep reference beam angle) holograms supported on a substrate having thin edge-illuminatable geometry. The system and process use thin edge-illuminated substrates that facilitate optimal coupling of the reference light beam at steep angles approaching grazing incidence, while maximizing the contrast of the slanted fringe structures thereof. Different recording techniques are employed when the index of refraction of the substrate is greater than that of the recording medium, than when the index of refraction of the substrate is less than that of the recording medium. A recording and playback system of complementary design is provided for recording slanted-fringe volume holograms under relaxed conditions, without compromising the light diffraction efficiency of the holograms under different playback conditions.

Abstract: A method and ultra-compact system has been developed for illuminating and detecting the surface topography of an object such as the finger (4) of an individual. The system (8) is capable of producing high-contrast images which can be electronically transmitted in real-time, or stored using electronic or photographic recording devices. Light traveling within a light transmitting substrate (2) is redirected by a slanted-fringed light diffractive grating preferably embodied within a volume hologram (3). The volume hologram (3), either of the reflection or transmission type, is attached to the light transmitting substrate (2). and functions to diffract light striking thereupon and illuminate an object having topographical surface structure. After being spatially and intensity modulated in accordance with topographical details of the illuminated object, the insulated light passes back through the light transmitting substrate (2) and the volume hologram (3), onto an image detection array. for subsequent analysis.

Abstract: A compact system for producing high contrast and high resolution images of a topographical surface associated with an object. The system utilizes a novel holographic optical element to produce images of topographical surfaces differentiating between ridges and valleys, and providing image details of artifacts. The system of the present invention can be realized in the form of a hand-held instrument for use in in vivo imaging of fingerprint, skin tissue and the like.

Abstract: A method and ultra-compact system has been developed for illuminating and detecting the surface topography of an object such as the finger of an individual. The system is capable of producing high-contrast images which can be electronically transmitted in real-time, or stored using electronic or photographic recording devices. Light traveling within a light transmitting substrate is redirected by a slanted-fringe light diffractive grating preferably embodied within a volume hologram. The volume hologram, either of the reflection or transmission type, is attached to the light transmitting substrate, and functions to diffract light striking thereupon and illuminate an object having topographical surface structure. After being spatially and intensity modulated in accordance with topographical details of the illuminated object, the modulated light passes back through the light transmitting substrate and the volume hologram, onto an image detection array, for subsequent analysis.

Abstract: A method and system for recording and displaying grazing-incidence (i.e., steep reference beam angle) holograms supported on a substrate having thin edge-illuminatable geometry. The system and process of the present invention uses thin edge-illuminated substrates that facilitate optimal coupling of the reference light beam at steep angles approaching grazing incidence, while maximizing the contrast of the slanted fringe structures thereof. A recording medium is in direct contact with a thin substrate whose refractive index is greater than the bulk refractive index of the recording medium. At the substrate interface, the recording medium has a gradient-type index matching region, created by exposure of the recording medium to reference beam illumination, prior to the further application of an object beam to create a fringe pattern.

Abstract: A method and system for recording and displaying grazing-incidence (i.e., steep reference beam angle) holograms supported on a substrate having thin edge-illuminatable geometry. The system and process of the present invention uses thin edge-illuminated substrates that facilitate optimal coupling of the reference light beam at steep angles approaching grazing incidence. Different recording techniques are employed when the index of refraction of the substrate is greater than that of the recording medium, than when the index of refraction of the substrate is less than that of the recording medium.