Improved holographic system has high degree of resolution and capability of providing a hologram of a moving object without requiring that the system have a high mechanical stability

Kurtz, R. L.

Norden, B. N.

English

NASA Technical Reports Server

June 1972	 B72-10260 
NASA TECH BRIEF 
Marshall Space Flight Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Hybrid Holographic System 
The problem: 
Holograms are normally produced by either one of 
two methods: the reflection method or the direct 
method. The reflection method reflects the signal beam 
from the test object in a forward direction to the photo-
graphic plate. When a hologram taken by this method is 
reconstructed, the test object is displayed with excellent 
resolution, since it is illuminated from the front. How-
ever, this method has the disadvantage of requiring that 
both the test object and the holographic system be 
mechanically stable (essentially motionless). In the 
direct method, the laser beam is transmitted through or 
by the test object after having first passed through a 
diffuser plate positioned between the laser light source 
and the test object. The direct method has the advantage 
of partially relaxing the stringent requirements for 
mechanical stability but has the disadvantage of poor 
resolution of the test object's front surface detail, since 
the object is illuminated only from the back. 
The solution: 
An improved holographic system has been designed 
with a high degree of resolution and a capability of pro-
viding a hologram of a moving object, without requiring 
that the system have a high mechanical stability. 
How it's done: 
The holographic system accomplishes these objectives 
by employing three beams: two beams are modulated by 
the test object, one in the reflection method, the second
in the direct method. The third beam serves as a refer-
ence. The beams are oriented so as to cause both modu-
lated beams to interfere with one another as well as with 
the reference beam. The beam paths are oriented with 
respect to the motion of the test object so that any 
change in beam-path length during the exposure time 
will not adversely affect the interference patterns be-
tween the beams. Additionally, the system's requirement 
is relaxed by using a light diffuser in the reflection path. 
Note: 
Requests for further information may be directed to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Code A&TS-TU 
Huntsville, Alabama 35812 
Reference TSP72- 10260 
Patent status: 
This invention has been patented by NASA (U.S. 
Patent No. 3,535,014), and royalty-free license rights 
will be granted for its commercial development. Inquiries 
about obtaining a license should be addressed to: 
Patent Counsel 
Code A & TS-PAT 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Source: Robert L. Kurtz and B. N. Norden

Marshall Space Flight Center 
(M FS-20074) 
Category 03 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
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Hybrid holographic system

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