Abstract

There has been much recent interest in infrared-transmitting materials because of their potential of becoming the next generation of optical communication fibers. One of these polycrystalline fibers, thallium bromo-iodide (commonly known as KRS-5), is considered to be a good candidate because it is both transparent down to 25 μm and, unlike fluoride glasses, is not hygroscopic. Moreover, it has been found that the long 10.6-μm wavelength is strongly absorbed by animal tissues and thus the combination of a CO₂ laser with a KRS-5 fiber would be good choice for medical surgery. Usually, fibers of KRS-5 are extruded continuously from a high-pressure ram extrusion apparatus; thus it is important to understand the effect of pressure on the optical properties of KRS-5 fibers, particularly as pressure has been shown to induce a large red shift in the optical absorption edges of thallium halide salts. Furthermore, it is not clear whether the frequency shift is a reversible process in KRS-5 and thus whether the pressure used in the manufacturing process will have an impact on the transmitting characteristics of the final products.

Anisotropic acousto-optic interaction in a KRS-5 crystal

V. S. Khorkin, V. B. Voloshinov, and M. S. Kuznetsov
Appl. Opt. 61(15) 4397-4403 (2022)

Attenuation at 10.6μm in loaded and unloaded polycrystalline KRS-5 fibers

James A. Harrington and Arlie G. Standlee
Appl. Opt. 22(19) 3073-3078 (1983)

KRS-5 optical fibers capable of transmitting high-power CO₂ laser beam

S. Sakuragi, M. Saito, Y. Kubo, K. Imagawa, H. Kotani, T. Morikawa, and J. Shimada
Opt. Lett. 6(12) 629-631 (1981)

Interferometric Observations of Yield in Thallium Bromo-Iodide

W. C. Levengood and William L. Wolfe
Appl. Opt. 5(12) 1919-1921 (1966)

Wavelength-dependent model of Kr flash lamp emission and absorption

Piero Mazzinghi and Daniele Bigazzi
Appl. Opt. 36(12) 2473-2480 (1997)