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Thulium lasers operating near approximately 2 microm are the subject of interest for various medical applications. The newly developed Tm3+ silica fibre laser in Q-switched and CW operation was investigated to determine its efficiency in the interaction with soft and hard tissues. The interaction was investigated using a free-running continuous (CW) Tm(3+)-doped fibre laser (wavelength 1.99 microm, with self-pulsation ranging over 1 to few tens of microseconds) and for novel Q-switched operation of the same fibre laser (pulse durations from 150 to 900 ns and pulse repetition rates from 100 Hz to 17 kHz). Residual damage and affected zones using the Q-switched laser were nearly six times smaller than using the CW fibre laser for about 50 s of exposure time, and increased with pulse repetition rate. The energy required to ablate tissue with the Q-switched fibre laser ranged from 0.2 to 0.6 kJ/cm3 and was significantly smaller than that for the CW fibre laser of 153 to 334 kJ/cm3. Under both high-resolution reflected optical microscopy and histological examination, tissue crater depths were observed as cleanly cut with smooth walls and minimal charring in the case of Q-switched operation of the fibre laser. This study is the first direct comparison of tissue interaction of short-pulse (Q-switched) and CW Tm(3+)-doped silica fibre lasers on crater depth, heat of ablation and collateral damage. The Q-switched Tm(3+)-doped silica fibre laser effectively ablates tissue with little secondary damage.

A peak output power of greater than 4.1 kW and a pulse duration at FWHM of 150 ns have been obtained in a Q-switched Tm3+-doped silica fiber laser in the wavelength region near 2 microm when the laser was pumped with a Nd:YAG laser operating at 1.319 microm. An acousto-optic modulator was used as a Q-switching element and operated at repetition rates of as much as 30 kHz. A core diameter of 17 microm was used to increase the laser gain volume, permitting high-pump-power absorption and an output of high pulse energy and peak power. Stimulated Brillouin scattering was directly observed in the output pulse, and as much as 10 orders of stimulated Brillouin scattering was recorded. This is the first report to the authors' knowledge of high-peak-power operation of a Tm3+-fiber laser.

In this work the crystal structure by single crystal X‐ray measurement and optical properties of 1D propane‐1,2‐diammonium pentachlorobismuthate [NH3CH2CH(NH3)CH3]BiCl5 organic–inorganic hybrid perovskite are presented. It is prepared by mixing ethanolic solution of equimolar ratios (1:1) of its basic components. The title compound crystallized in the noncentrosymmetric orthorhombic space group Pca21 with Z = 8 molecules per unit cell. The unit‐cell parameters are a = 19.8403 (7) Å, b = 6.3303 (2) Å, c = 19.0314 (7) Å. The vibrational spectra are studied by Raman and infrared spectroscopy. The optical properties show a strong absorption in the ultraviolet region, the band gap energy Eg is found to be 3.15 eV. Cathodoluminescence measurements are also discussed.

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