Controlling Fringe Sensitivity of Electro-Optic Holography Systems Using Laser Diode Current Modulation (Paperback) (ISBN-13: 9781288911059)

Electro-Optic Holography (EOH) is a non-intrusive, laser-based, displacement measurement technique capable of static and dynamic displacement measurements. EOH is an optical interference technique in which fringe patterns that represent displacement contour maps are generated. At excessively large displacements the fringe density may be so great that individual fringes are not resolvable using typical EOH techniques. This thesis focuses on the development and implementation of a method for controlling the sensitivity of the EOH system. This method is known as Frequency Translated Electro-Optic Holography (FTEOH). It was determined that by modulating the current source of the laser diode at integer multiples of the object vibration, the fringe pattern is governed by higher order Bessel function of the first kind and the number of fringes that represent a given displacement can be controlled. The reduction of fringes is theoretically unlimited but physically limited by the frequency bandwidth of the signal generator, providing modulation to the laser diode. Although this research technique has been verified theoretically and experimentally in this thesis, due to the current laser diode capabilities it is a tedious and time consuming process to acquire data using the FTEOH technique.

Author: National Aeronautics and Space Administr,Shannon J. Bybee
ISBN-10: 128891105X
ISBN-13: 9781288911059
Publisher: Biblioscholar
Language: English
Published: 03/12/2013
Pages: 152
Format: Paperback
Weight: 0.63lbs
Size: 9.69h x 7.44w x 0.33d