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OPTICAL SECOND HARMONIC GENERATION IN ORGANIC CRYSTALS: UREA AND AMMONIUM-MALATE
BibTeX
@MISC{Betzler_opticalsecond,
author = {R. Betzler and H. Hesse and P. Loose and Universitzt Osnabriick},
title = {OPTICAL SECOND HARMONIC GENERATION IN ORGANIC CRYSTALS: UREA AND AMMONIUM-MALATE},
year = {}
}
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Abstract
Optical second harmonic generation (SHG) has been investigated in single-crystals of urea and ammonium-malate (AM). Phase match angle, refractive indices, and all nonvanishing coefficients of the non-linear susceptibility tensor have been measured. A comparison to KDP shows, that AM is comparable to KDP, urea much more efficient in SHG than KDP, The measurements were performed with a flash-lamp pumped dye laser which could be tuned from 480 nm to 640 nm using different dyes (mainly coumarins and rhodamines). The crystals were gro-wn from solution and had a typical size of 5 x 10 x 10 mm3 in the case of urea and 15 x 15 x 10 mm3 in the case of AM, respectively, after cutting and polishing. They could be rotated in the laser beam around a horizontal and a vertical axis, so that all desired crystal directions for the incident polarization could be achieved. For the detection of the second harmonic signal served a solar-blind photomultiplier with CST.e photocathode, the signal of which could either be displayed on an oscilloscope or be averaged by a gated integrator. 1. Urea (CO(NH2)21 From powder measurements the high nonlinear optical susceptibility of urea is well known (1). Our measurements show that efficient phase-matched frequency doubling is possible over a wide spectral range. In urea (crystallographic class D2d (a2 m) (2) ) only the 394 3 three components x l3 = x il = x l2 of the nonlinear optical susceptibility tensor are non-zero: phase matched frequency doubling of type II is possible for the two equivalent components x:, [as the crystal. is optically positive uniaxial). ii! cl., 5cm 550 h WAVELENGTH R-ky
Keyphrases
refractive index solar-blind photomultiplier vertical axis second harmonic signal efficient phase-matched frequency doubling wavelength r-ky frequency doubling incident polarization nonvanishing coefficient equivalent component nonlinear optical susceptibility tensor crystal direction l3 il l2 laser beam ii cl wide spectral range gated integrator powder measurement non-linear susceptibility tensor optical second harmonic generation phase match angle different dye flash-lamp pumped dye laser typical size high nonlinear optical susceptibility crystallographic class d2d kdp show type ii
