NONLINEAR OPTICAL MATERIALS

ORGANIC CRYSTALLINE MATERIALS HAVE BEEN REPORTED AS HAVING OPTICAL NONLINEAR COEFFICIENTS 10 TO 200 TIMES THAT OF CONVENTIONAL INORGANIC MATERIALS. 2-METHYL-4-NITROANILINE (MNA), IS ONE SUCH MATERIAL. ITS PROPERTIES HAVE BEEN EVALUATED BY THE SECOND-HARMONIC POWDER TECHNIQUE AND EXPERIMENTS USING THIN PLATES OF MNA CRYSTALS OF VARIABLE OPTICAL QUALITY. THE REPORTED NONLINEAR COEFFICIENTS FOR MNA ARE D11=150PM/V AND D12=23PM/V. THE ELECTRO-OPTIC COMPONENT, R11, HAS BEEN REPORTED TO BE 67+/_25X20(-12)M/V. GIVEN THESE PROPERTIES, MNA MAY BE USEFUL FOR HARMONIC GENERATION OF LOW INTENSITY SOURCES AND OPTICAL SWITCHING. UNFORTUNATELY, MNA IS NOT AVAILABLE AS LARGE HIGH QUALITY SINGLE CRYSTALS. THE OBJECTIVE OF THIS PROPOSAL IS TO INVESTIGATE THE VARIOUS GROWTH PARAMETERS NECESSARY TO ESTABLISH A SOLUTION GROWTH METHOD FOR MNA IN ORDER TO GROW LARGE HIGH QUALITY CRYSTALS. THESE SHOULD BE OF SUFFICIENT SIZE TO ALLOW ACCURATE, QUANTITATIVE TESTING OF TRANSMITTANCE, BULK DAMAGE THRESHOLD AND SHG EFFICIENCY. THE CRYSTALS WILL BE GROWN IN A MODIFIED HOLDEN TEMPERATURE LOWERING CRYSTALLIZER. TO BE SUCCESSFUL,IMPURITIES, TEMPERATURE FLUCTUATIONS AND SPURIOUS NUCLEI MUST BE KEPT TO A MINIMUM. THIS RESEARCH COULD LAY THE BASIS FOR A COMMERCIAL MNA CRYSTAL GROWTH METHOD WHICH MIGHT ALSO BE APPLICABLE TO OTHER ORGANIC CRYSTALS.