Accession Number : ADA298468

Title :   Experimental Study of Nonlinear Periodic Structures.

Descriptive Note : Final rept. Apr 91-Apr 95,

Corporate Author : LEHIGH UNIV BETHLEHEM PA DEPT OF PHYSICS

Personal Author(s) : Malcuitt, Michelle S. ; Herbert, Christopher ; Heid, Christy

PDF Url : ADA298468

Report Date : MAY 1995

Pagination or Media Count : 67

Abstract : The optical properties of two examples of nonlinear periodic structures experimentally studied: colloidal crystals used as nonlinear distributed feedback structures and nonlinear volume holographic elements. The transmission of the colloidal crystals was found to be dramatically modified by an incident field whose frequency was tuned within or near the stop gap of the crystal. Optical limiting was observed when the frequency of the incident field was tuned to the high frequency edge of the stop gap. Optical switching and bistability were observed when the frequency was tuned to within the stop gap. The switching intensity was seen to decrease as the frequency of the incident light was tuned further into the stop gap. This result can not be explained by the simple model of a nonlinear distributed feedback structure. The transmission was also found to exhibit temporal fluctuations at high intensities. The nonlinear volume holographic structures consisted of a porous photopolymer in which a permanent grating was recorded and then was imbibed with a nematic liquid crystal. The diffraction efficiency of the grating was switched from high to low using a control beam power of 8.4 mW. The response time of the switching was limited by the response time of the thermal nonlinearity of the liquid crystal and was measured to be approximately 1 ms. (MM)

Descriptors :   *NONLINEAR OPTICS, *LIGHT TRANSMISSION, *OPTICAL SWITCHING, THERMAL PROPERTIES, OPTICAL PROPERTIES, HIGH FREQUENCY, POLYMERS, REACTION TIME, INTENSITY, REFRACTIVE INDEX, LIQUID CRYSTALS, GRATINGS(SPECTRA), HOLOGRAPHY, NONLINEAR SYSTEMS, DIFFRACTION, COLLOIDS, POROUS MATERIALS, PERIODIC VARIATIONS, HOLOGRAMS, DISTRIBUTED AMPLIFIERS.

Subject Categories : Electrooptical and Optoelectronic Devices
      Optics
      Numerical Mathematics

Distribution Statement : APPROVED FOR PUBLIC RELEASE