Absorption coefficients and scattering losses of TGG, TGP, KTF, FS, and CeF<sub>3</sub> magneto-optical crystals in the visible via cavity ring-down spectroscopy
Michalis Xygkis, Artemis Linaraki, Eirini Toutoudaki, George E. Katsoprinakis, T. Peter Rakitzis
Abstract
We demonstrate a method for determining small absorption coefficients and surface-scattering losses of crystals using cavity ring-down spectroscopy and perform measurements on magneto-optical crystals of terbium gallium garnet (TGG), terbium gallium phosphate (TGP), fused silica (FS), potassium terbium fluoride (KTF), and CeF 3 at 532 and 634 nm. Surface scattering is distinguished from absorption losses by using crystals of different lengths. A figure of merit (FoM) for magneto-optical crystals is defined to evaluate their suitability as intracavity optics in optical cavity applications. It is found that TGP has the highest FoM for crystal lengths up to ∼10mm, whereas CeF 3 and FS potentially outperform TGP for longer crystals. Single-pass applications are also briefly discussed.