Stable continuous-wave mode-locked laser from a 1645 nm Er:YAG ceramic oscillator

We demonstrate stable continuous-wave mode-locking (CWML) pulses around 1645nm by employing the home-made Er:YAG ceramic. By using a fiber laser and semiconductor saturable absorber mirror (SESAM) with modulation depth of 1.2%, we get ML pulses with the output average power up to 815 mW, the pulse width shortened as ~4 ps, and the peak power of 1.8 kW. With the SESAM of modulation depth of 2.4%, the second-order harmonic ML pulses were also obtained. As far as we know, this is the first report of CWML from Er3+-doped ceramics and also the shortest pulse duration in Er3+-doped solid-state oscillators.

Standoff Detection of Oil and Powder Mixtures at 12 Meters Using a Tunable Quantum Cascade Laser-Based System with a Close Focus Telescope and Uncooled Infrared Detector

We have designed and demonstrated a quantum cascade laser (QCL) based standoff system that utilizes an uncooled mercury cadmium telluride (MCT) detector with lock-in signal processing for chemical identification at a distance of 12.5 meters in indoor ambient light conditions. In the system, a tunable quad-QCL operating (1 MHz) in quasi-continuous wave mode between 8.45 and 10.03 μm (∼1182 to 1000 cm−1) serves as the active mid-infrared source for remotely interrogating mineral, powder, and thin film oil samples including powder mixtures (6, 12.5, 25, and 50%) of crystalline quartz (SiO2) in KBr. Light as reflected from a given sample is collected using a 10-inch (25.4 cm) Dall Kirkham telescope and coupled with ZnSe optics to an uncooled MCT detector. The mixture dependence of the highly transparent KBr and strongly absorbing quartz was found to fit a modified version of the Schatz reflectance model for compacted powder mixtures. All reflectance spectra reported are relative to an Au-coated diffuse reflector. A NIST traceable polystyrene standard reflector was also used to determine the QCL wavelength tuning range and calibration.

The Evaluation of the Effectiveness of the Optimized Technique of Transcleral Diodlaser Cyclophotocoagulation in Patients with Unstable Glaucoma

Objectives: To evaluate the effectiveness of the optimized technique of transcleral diode laser cyclophotocoagulation (DCPC) in patients with unstable glaucoma.Methods. The retrospective analysis of outpatient records of patients diagnosed with open-angle compensated glaucoma, who underwent transcleral diodlaser DCPC in continuous-wave mode, has been performed. Totally, 44 outpatient records (44 eyes) have been analyzed.Results. The course of the postoperative period, patients’ complaints, and the ophthalmological status have been evaluated. The level of intraocular pressure (IOP) was determined on the day after the procedure, a week, 1, 3, 6 and 12 months after the operation. 12 months after the operation, the level of IOP decreased by 42.9 %. The number of antihypertensive drugs used by the end of the follow-up period decreased by 66.6 %: from 2.75 ± 0.4 to 1.0 ± 0.7 drugs (p = 0.001). The frequency of side effects was low and comprised 11.3 %. In 40 % of patients, manifestations of toxic-allergic reactions of the ocular surface to antihypertensive drugs decreased due to the possibility to reduce the frequency of instillations. The MCVA indicators remained stable throughout the entire follow-up period.Conclusion. Thus, the results of the conducted clinical study indicate that transcleral DCPC is an effective and safe technique with a high predicted result, since it compensates for the level of IOP, which allows to stabilize the progression of the glaucoma process. The method of trascleral DCPC provides a reduction and (or) correction of the hypotensive regime by reducing the number of antihypertensive drugs used. In patients with a toxic-allergic reaction from the ocular surface developed due to a prolonged use of antihypertensive drugs, it allows to reduce the symptoms and clinical manifestations by canceling and (or) reducing the number of antihypertensive drugs used, indirectly significantly improving the quality of life.