All-space existence and dispersion of athermal directions in monoclinic KY(WO4)2

Abstract

a b s t r a c tThe analytical expressions for thermo-optic coefficients, dn/dT, for "fast" and "slow" light waves propagating along the arbitrary direction in a biaxial crystal are derived. On the basis of these expressions, the all-space analysis of existence of athermal directions is performed for monoclinic and biaxial KY(WO 4 ) 2 at 1.03 μm. The calculations are performed for an arbitrary light propagation direction and polarization (not restricted to the principal planes). The appearance of directions that can be athermal for both "fast" and "slow" waves is predicted. The dispersion of athermal directions is analyzed for visible and near-IR. The existence of upper and lower dispersion limits for athermal behavior of KY (WO 4 ) 2 is shown. It is shown that the optical indicatrix axes can be athermal itself at some light wavelengths. Wavelength-and temperature-dependent position of the optical axes of KY(WO 4 ) 2 is also determined.

Laser action along and near the optic axis of a holmium-doped KY(WO_4)_2 crystal

“…The cutting angle of the crystal was 18°between the crystallographic c-axis and the dielectric axis N g . The cutting angle between the optic axis and the N g axis was 44°, which is closed to the values given in [17]. However, the misalignment with respect to the optic axis at 2 μm is close to ∼1°using those angles.…”

Watt-level ultrafast laser inscribed thulium waveguide lasers

“…The thermo-optical effects in MDTs can be greatly suppressed owing to their "athermal" behavior [51,52], i.e., a mutual compensation of contributions to the variation of the optical path length arising from the negative thermo-optic coefficients (dn/dT < 0) [53] and positive thermal expansion [54]. These properties lead to a weak, positive and nearly spherical thermal lens for certain crystal orientations with a reduced effect on the laser mode [55][56][57][58][59].…”