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Highly efficient laser oscillations at 2 μm were investigated in Tm:Lu₂O₃ ceramics in-band pumped at 1670 nm by a Raman-shifted erbium fiber laser. Both 23 W CW and 15 W active Q-switched oscillations with 40 ns pulse duration and 15-30 kHz repetition rate were achieved in a high-quality beam. The evolution of two generated waves at 1966 and 2064 nm in dependence on pump power was studied.

Structural, optical and spectroscopic properties of Tm3+:Lu2O3 ceramics were studied. CW laser operation at 2068 nm with an output power of up to 34 W and a slope efficiency of 44% was obtained. Q‐switched ocsilation with a pulse duration of 100‐150 ns and a repetition rate of 1‐10 kHz was achieved. Passive mode locking was achieved using an ion‐implanted InGaAsSb quantum‐well based SESAM or single graphene layer. Transform‐limited pulses as short as 180 fs are generated at 2076 nm with an average output power of 400 mW and a pulse repetition frequency of 121.2 MHz. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

A laser oscillator based on Cr 2+ :CdSe single crystal pumped by 2.066 µm radiation of a Tm 3+ :Lu 2 O 3 ceramic laser was created and investigated. Repetitively pulsed oscillations at a wavelength of 2.92 µm with a bandwidth of 80 nm were demonstrated. The output power was up to 350 mW at 10 kHz repetition rate with a pulse duration of ~200 ns in the good-quality beam.

Spinal muscular atrophy (SMA) is characterized by the degeneration of spinal alpha motorneurons. Nusinersen demonstrated good efficacy in the early disease phases. The feasibility of transcutaneous spinal cord stimulation (tSCS) in motor rehabilitation of patients with spinal cord injury has been demonstrated. We hypothesize that tSCS may activate intact and restored by nusinersen motorneurons and slow down the decline in motor activity, and may contribute to the development of motor skills in children with SMA. A case series is presented. Five children (6–13 years old) with SMA type II or III participated in the study. They were treated with nusinersen for ~2 years. Application of tSCS was carried out during physical therapy for 30–40 min per day in the course of 10–14 days. Outcome measures were goniometry of joints with contracture, forced vital capacity (FVC), RULM and HFMSE scales. The participants tolerated the stimulation well. The reduction of the contracture was ≥5 deg. RULM and HFMSE increased by ~1–2 points. Predicted FVC increased by 1–7% in three participants. Each participant expanded their range of active movements and/or learned new motor skills. Spinal cord stimulation may be an effective rehabilitation method in patients treated with nusinersen. More research is needed.

The structural, optical, and spectroscopic properties of new Tm 3+ : Lu 2 O 3 laser ceramics are studied. The average size of a ceramic grain (crystallite) is found to be 540-560 nm. The absorption spectrum measured in the near-IR region shows that this ceramics can be pumped by commercially available laser diodes at wavelengths of 796 and 811 nm. The high-transmission region of the ceramics in the mid-IR region extends to 7 mm. Investigations of the luminescence spectrum in the region of 1.75-2.2 mm upon laserdiode pumping show strong lines peaked at wavelengths of 1942, 1965, and 2066 nm. Ellipsometric measurements yield refractive indices n » 1.92 at the pump wavelength 796 nm and n » 1.94 at the laser wavelength 2066 nm. Continuous-wave lasing of a Tm 3+ : Lu 2 O 3 ceramic laser at a wavelength of 2066 nm is demonstrated under diode-laser pumping at wavelengths of 796 and 811 nm.

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