Methods for specifying and evaluating light-based media and devices have become commonplace in various industries such as the professional luminaire industry. This is not the case with Holography as there are no standards that address specifying, evaluating, and displaying holograms. If methods are considered, then standards can be addressed. Three measurable characteristics of holograms are considered. This paper reviews Kelvin temperature for correct color rendition, goniometry for hologram angle of view, and signal-to-noise ratios for efficiency. This paper is relevant to the independent holographer or anyone contracting a hologram facility to custom produce holograms that are reconstructed with a white point source of light. The focus of this paper is analog image / light pattern holograms for display.
A spectrograph is described which is made with dual Holographic Optical Elements (HOEs) which are identical and parallel to each other. Both optics are collimating transmission HOEs with focal points that are at equal and opposite distances from each other. The identical HOEs are formed by the interference of a plane wave parallel to the grating plane with an off-axis spherical wave originating in the near-field. In playback, a spectrum can be formed from a point source radiator placed at the position of the recording spherical wave. If played back at an arbitrary wavelength other than the recording wavelength, the image exhibits coma. This spectrograph is intended for an unusual configuration where many nearly monochromatic sources of known wavelengths are separately positioned relative to the first HOE. The special application is in a space telescope capable of resolving spectra from habitable planets within 10 pc. HOEs of this type could be fabricated on membrane substrates with a low areal mass and stowable on rolls for insertion into the second Lagrange point. The intended application is for a 50 x 10 meter class primary objective holographic space telescope with 50 x 10 m HOEs in the spectrograph. We present a computer model of the spectrograph.. Experimental results are compared with predictions from theory. A single HOE is shown to perform over a wider bandwidth and is demonstrated.
This paper will discuss projects that have been completed based on results of fabrication techniques and accelerated aging tests which expand the range of design applications possible with embossed materials. Installation of this value added material on a permanent or semi- permanent basis also makes it economically feasible to include dedicated illumination systems which bring out the full spectral potential of these materials.