ABSTRACT
We introduce an approach for the temperature stabilization of nonlinear-optic crystals during laser frequency conversion processes. This approach is based on the stabilization of the piezoelectric resonance (PR) frequency of the crystal, so that the crystal itself becomes a temperature sensor. Application of an electronic oscillator provides a remarkably handy way to determine the PR frequency. When the PR frequency stabilization was employed, the stable generation of the second harmonic (SH) at 532 nm wavelength was achieved in periodically poled lithium niobate (PPLN) at more than 30% power compared to the case of the application of external temperature sensors. Long-term stability of SH power was also enhanced.
ABSTRACT
We have introduced an approach for low optical absorption coefficient measurement of piezoelectric materials based on the piezoelectric resonance laser calorimetry (PRLC) method. An RF oscillator circuit provides a convenient way to track the piezoelectric resonance frequency during laser irradiation. In this work, the optical absorption coefficient of lithium triborate crystal under high-power IR laser irradiation was measured using the oscillator circuit and the conventional PRLC technique.
ABSTRACT
Temperature dependence of the dielectric losses conditioned by the ionic conductivity (IC) of nonlinear optical lithium triborate (LBO) crystals was investigated both theoretically and experimentally, exploiting the variation of the line form of LBO piezoelectric resonances with temperature. An effect of the IC on the optical properties of LBO crystals was considered. The relation between the LBO IC and its resistance to UV radiation was investigated.
ABSTRACT
A novel method for the precise temperature measurement of active fibers in high-power fiber lasers and amplifiers is introduced. This method allows the determination of active fiber longitudinal temperature distribution at different optical pump powers.
