The 2.94 μm Er:YAG laser Q-switched mechanically by a rotating mirror was developed. The laser generated pulses of 30 mJ energy and duration below 290 ns, which corresponds to over 100 kW peak power. It operated at the repetition rate of up to 25 Hz. To our knowledge it is the most powerful erbium laser operating at so high repetition rate. The developed laser can be successfully applied in medicine -e.g. in microsurgery of soft biological tissues.Laser beam interaction with a gelatin sample

We demonstrate a novel method of mid-infrared (mid-IR) supercontinuum (SC) generation with the use of a 2 µm gain-switched self-mode-locked thulium-doped fiber laser. SC radiation ranging from ~1.9 to 3.8 µm wavelength, generated in a single-mode ZBLAN fiber with a zero-dispersion wavelength (ZDW) shifted to ~1.9 µm, is reported. An average output power of 0.74 W with 0.27 W at wavelengths longer than 2.4 µm was measured. It is, to the best of our knowledge, the first report on such an approach to generate a mid-IR SC in optical fibers.

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A diode-pumped actively Q-switched and actively mode-locked Tm3+-doped double-clad silicate fiber laser is reported providing up to 5 W of average output power at ~60 kHz Q-switch envelope repetition rate and ~8 μJ subpulses with up to 2.4 kW peak power. Using this source as a pump laser for supercontinuum generation in a ZBLAN fiber, over 1080 mW of supercontinuum from 1.9 μm to beyond 3.6 μm was obtained at an overall efficiency of 3.3% with respect to the diode pump power.

Mid-infrared supercontinuum (SC) generation in a thulium fiber amplifier is reported. The system delivered an average output power of 2.37 W in a spectral band of ∼(1.75–2.7) μm which is, to the best of our knowledge, the highest average power of SC generated from a single-mode Tm-doped fiber. For wavelengths longer than 2.4 μm, the output power was as high as 0.49 W, constituting almost 21% of the total output power. A 10 dB spectral flatness in the wavelength interval ranging from 1.95 to 2.52 μm (570 nm span) with a corresponding (calculated) spectral power density greater than 3 mW nm−1 is demonstrated. Amplification in both emission bands of Tm3+ ions, as a way to effectively enhance SC generation towards longer wavelengths, is also discussed.

Abstract. The paper presents an analysis of influence of ambient temperature changes on the values of parameters in topography measurements with the use of different profilometry techniques. In order to check this, a series of measurements was performed. Two multiprofilometry instruments were used -a contact profilometer, further equipped with an interferometric transducer, and an optical one with a confocal probe. Measurements were performed on first-class flat interferometric glass and on an A-type roughness standard -under different conditions, with simultaneous registration of differences in ambient temperature values. These values were either intentionally changed or the temperature variations were the result of air conditioning control. The performed research showed that -despite the asperities on the surface being really small -there is a relationship between changes of temperature and the results obtained from the measured surface, which in some cases can be seriously distorted.

An actively Q-switched Er:YAG laser generating pulses at 2.94 microm has been developed and investigated. For a single Er:YAG generator at 3 Hz repetition rate, pulses of 91.2 ns duration and 137 mJ energy have been obtained. It corresponds to pulse train with high-peak power of ~ 1.5 MW. For 10 Hz repetition rate 30 mJ of output energy in single pulse has been achieved. These results, according to our knowledge, are the best world-wide achievements.

We report high-power supercontinuum (SC) generation in a step-index fluorozirconate (ZBLAN) fiber with a zero-dispersion wavelength shifted to ~1.9  μm. Pumping the fluoride fiber with 2.75 W of power provided by a thulium-doped fiber amplifier, a continuous spectrum extending from ~0.85 to 4.2 μm with 2.24 W of average output power was achieved. Over 61% (1.37 W) of the total output power corresponds to wavelengths longer than 3 μm, which shows, to the best of our knowledge, the highest power conversion efficiency toward the mid-IR spectral band in relation to the output spectrum width. A linear SC power scalability up to 5.24 W, with a spectral band of ~0.9-4  μm, with repetition rate and pump power provided by a 1.55 μm fiber master-oscillator power amplifier system, is also demonstrated.