Equivalent temperature stabilization of nonlinear-optical crystals.

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.

RF oscillator circuit for absorption coefficient measurement of piezoelectric materials.

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.

Precise measurements of the low optical absorption coefficients of massive lithium triborate crystal boules with untreated facets formed during the growth process.

A spatial diagnostic of optical quality of the massive lithium triborate crystal boule with untreated facets was performed by measuring optical absorption coefficients at 1070 and 1908 nm wavelengths using the piezoelectric resonance laser calorimetry technique.

Radiofrequency impedance monitoring of the biological tissues under local heating by optical radiation.

Development of methods for simultaneous control of state of biological tissues during optical treatment is the important tasks in laser surgery. We introduce a novel approach for the monitoring of the state of biological tissues in the process of its local heating by optical radiation. It is based on measurements of the electrical radiofrequency impedance kinetics of the sample during irradiation.

Radiofrequency impedance spectroscopy of biological tissues under heating by homogeneous laser radiation.

We have developed an original method to measure the temperature dependence of the biological tissue electrical properties based on its heating by homogeneous optical radiation.The conventional approach in hyperthermia research involves heating due to a thermal conductivity through the surface of the sample. The novel technique is based on the emission of heat sources in the sample volume caused by the absorption of optical radiation.