Laser heating dynamics and glow spectra of carbon-, titanium- and erbium-containing optothermal fibre converters for laser medicine

Titanium- and erbium-containing optothermal fibre converters of laser radiation mounted at the distal end of quartz–quartz optical fibre are discussed for the first time. Technology of fabricating such converters is described. Carbon-containing converters are also considered. The laser heating dynamics of the converters and the glow spectra are studied by irradiating converters of each type by a 980 ± 10 nm semiconductor laser with an average power up to 4 W. It is shown that alongside with broadband thermal radiation accompanying the laser heating of all three types of converters in the temperature range 600–1100 °C, only in the spectrum of the erbium-containing converter the intense bands with the maxima at wavelengths 493, 523, 544, 660, and 798 nm, corresponding to the erbium radiative transitions ⁴F_7/2 → ⁴I_15/2, ²H_11/2 → ⁴I_15/2, ⁴S_3/2 → ⁴I_15/2, ⁴F_9/2 → ⁴I_15/2 and ⁴I_9/2 → ⁴I_15/2, respectively, are present. Such converters can be used in laser medicine for tissue surgery as well as in procedures combining laser, thermal, biostimulation or photodynamic action.