| Popis: |
The optical properties of LiInS2 suggested it as a promising material for generation of coherent radiation in the mid-IR region. Before investigating such capabilities its optical and mechanical properties have to be characterized precisely, and especially their evolution with temperature. Sufficiently large and suitably oriented crystals of good optical quality were studied. We first deduced the transparency range of these samples, as well as the frequencies of the optical phonons. We observed a phase- matched second-harmonic generation, using a nanosecond-OPO in the range 2.4 - 2.6 microns as the pump source and estimated a first value of the type-II nonlinearity deff(XY) equals 7.4 pm/V. The thermal expansion, thermo-optic, piezoelectric and electro-optic coefficients were determined along the three principal directions of polarization from -20 degrees Celsius up to + 120 degrees Celsius by means of original interferometric methods. A so-called Fabry-Perot Thermal Scanning (FPTS) interferometric method has been developed to measure accurately the electro-optic coefficients. For LiInS2 the values of ri3 were found to be of the same order of magnitude as its piezoelectric coefficients, but around one order of magnitude smaller than the electro-optic coefficients of the well known KTiOPO4.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. |
