Holograms. We have seen them work in futuristic movies. They are futuristic optical contraptions manipulated to reconstruct the light waves coming from scaled replicas of three-dimensional solid objects. Holography has been studied since the 1960s and many studies have been done for the enhancement of the technology of holography. One of them is the doctoral dissertation of Dr. Percival F. Almoro of the National Institute of Physics, which focuses on Full-Color Digital Holography (FCDH).
Holography [(gr.) holos all, total; grapho I write] is a branch of physics that studies processes of the transformation of waves by interference structures formed by coherent waves when they interact with matter. The ultimate goal of holography for imaging is to reconstruct optical waves of three dimensional, colored and moving objects in real time. To achieve the full-color aspect requires a multi-wavelength light source and a broadband light-sensitive recording medium. Conventional color holography, which can only be applied to stationary objects, utilizes several lasers and films, thus, is very expensive to build and often difficult to maintain. Thus, Dr. Almoro introduces a novel pulsed color holographic light source, the hydrogen Raman Shifter.
Raman Shifter as a potential holographic light source is compact, inexpensive, and a multi-wavelength pulsed coherent light source. With the use of a multi-wavelength pulsed laser, color application of holography is extended to fast moving objects and transient events. The digital mode of holography utilizes a digital camera as a reusable recording medium and a computer for rapid hologram reconstruction. Pulsed full-color digital holography, therefore, provides a fast and more complete representation of three-dimensional moving objects. There is one obstacle in FCDH though -- wavelength-dependence of image size and resolution that results in a blurred image. According to Dr. Almoro, a technique to control this chromatic dispersion is resizing the holograms using ratio of wavelengths and reconstructing at best-focused distances in order to create a clearer image representation of an object.
Now we know that the era we call future with cool and hi-tech gadgets such as the hologram is not so far from coming true after all.
This research study entitled Full-Color Digital Holography by Dr. Percival F. Almoro was published in an international publication, the Applied Optics*, Vol. 43, No. 11, 10 April 2004 issue. It was also cited in “Self-referenced measurement of the complete electric field of ultrashort pulses” by Pablo Gabolde and Rick Trebino in the Optics Express*, Vol. 12, No. 19, 20 September 2004 issue.
By MMRParreño
*Current journals of Optical Society of America: http://www.osa.org/journals/
