TEMPERATURE PROPERTIES OF LASER-INDUCED INTERFERENCE FILTERS IN LITHIUM-NIOBATE

The temperature properties of subangstrom bandwidth interference filte rs written in photorefractive lithium niobate crystals are investigate d. The temperature sensitivity of the center wavelength is described w ith a theoretical model based on the phase matching condition. The the ory is compared favorably with our experimental results, on unfixed fi lters at 413 nm and 514.5 nm, and with the work of other groups. A sen sitivity of 0.047 Angstrom/K and 0.104 Angstrom/K are measured for fil ters with the grating wave vector, respectively, parallel and perpendi cular to the c-axis. Using a novel method the spectral response is ded uced from combined angular and temperature response measurements. An a symmetry is observed in the filter response. A spectral bandwidth of 0 .05 Angstrom is estimated for a filter with a measured thermal bandwid th of 0.5 K, giving a temperature tuning range of 2 Angstrom and a sta bilization accuracy of 0.005 Angstrom.