[Stroke in children and adolescents].

Objective: A comparative analysis of symptoms in arterial ischemic and stroke-like conditions in children, the development and analysis of the «Presumptive stroke in children» scale for prehospital diagnosis of ischemic strokes in children.

Material And Methods: This article analyzes cases of emergency hospitalization of children in a stroke center with suspected cerebrovascular pathology as well as the symptoms of patients with suspected ischemic stroke, compares the leading and final diagnoses, identifies the main «mimics» of stroke and their symptom complexes. A comparison of the obtained data with the results of previous studies was carried out.

[Pre-hospital diagnosis of stroke in children. An analysis of the work of the First aid station in Moscow and the primary pediatric stroke center].

Objective: The article presents an analysis of pre-hospital diagnosis of stroke in children.

Material And Methods: Pediatric Stroke Center of Morozov Children's City Clinical Hospital (Center) for the period from October 2018 to December 2019, 502 cases of hospitalization of children by the First aid Station to the Center with directing diagnoses of ischemic stroke (IS), haemorrhagic stroke (HS), transient ischemic attack (TIA), vertebrobasilar syndrome (VBS) were analysed.

Results And Conclusion: TIA was the most prevalent diagnosis made by the First aid station, with the lowest rate of confirmation after further examination in the hospital (7.

Spectroscopic properties and continuous-wave deep-red laser operation of Eu-doped LiYF.

Eu-doped LiYF is reexamined as a laser material for the visible spectral region. Polarized absorption and emission cross sections as well as the fluorescence lifetime are determined. Branching ratios and radiative lifetime are calculated within the theory of 4f-4f transition intensities, which takes into account the influence of an excited configuration of the opposite parity 4f5d.

Passively Q-switched Pr:YLF laser with a Co:MgAlO saturable absorber.

We report on a 2ω-OPSL-pumped passively Q-switched Pr:LiYF laser operating at the wavelengths of 523, 607, and 640 nm. For this, we utilized a Co-doped MgAlO (MALO) crystal as a saturable absorber in the visible range for the first time, to the best of our knowledge. In the green spectral region, the pulse duration was 210 ns with a pulse energy of 3.

Growth, spectroscopy, and laser characterization of Er:KGdYbY(WO) epitaxial layers.

We report on the composition of Er-doped KGdYbY(WO) layers to be grown onto undoped KY(WO) substrate providing fine lattice matching and high refractive index contrast with the substrate and fabrication of high optical quality Er(1.3  at. %):KGdYbY(WO) epitaxial layers with thickness up to 180 μm.

Graphene Q-switched Er,Yb:GdAl(BO) laser at 1550 nm.

A single-layer graphene saturable absorber is employed for passive Q-switching of an Er, Yb:GdAl(BO) (Er,Yb:GdAB) compact laser, representing the first Er-doped oxoborate laser Q-switched by graphene. This laser is based on a c-cut 1.8 at.

Diode-pumped Tm:KY(WO) laser passively modelocked with a GaSb-SESAM.

We present the first diode-pumped modelocked thulium (Tm) laser based on a double-tungstate crystalline gain material. The solid-state laser consists of a Tm:KY(WO) crystal as gain medium and a GaInSb/GaSb quantum well saturable absorber for self-starting passive mode locking. The laser is pumped by a multi-mode fiber-coupled laser diode at a wavelength of 793 nm.

Yb:LuAlO crystal as a gain medium for efficient broadband chirped pulse regenerative amplification.

The experimental study results of a chirped pulse amplification regime are reported for the Yb:LuAlO crystal with different polarization states in the gain media for the first time, to the best of our knowledge. Maximum output power of 5 W with 565 fs pulse duration was obtained for E//b-polarization at a 200 kHz repetition rate seeded by a 98 fs Yb:KYW oscillator. 165 fs pulses with output power of 4.

Spectroscopy and continuous wave laser performance of Yb:LuAlO crystal.

Crystal growth, polarized spectroscopic properties, lifetime measurements, and CW laser performance under diode pumping of a new Yb-doped LuAlO crystal (Yb:LuAP) are reported for the first time, to the best of our knowledge. The maximum absorption cross section of 6.6·10  cm at 978.

Yb:CaYAlO-based chirped pulse regenerative amplifier.

The results of an experimental study of the chirped pulse amplification regime are reported for the Yb:CaYAlO crystal with different polarization states in the gain media for the first time, to the best of our knowledge. A maximum output power of 4.2 W with 310 fs pulse duration was obtained for σ-polarization at 200 kHz repetition rate seeded by a 85 fs Yb:KYW oscillator.

Energy transfer in Tm,Ho:KYW crystal and diode-pumped microchip laser operation.

An investigation of Tm-Ho energy transfer in Tm(5at.%),Ho(0.4at.

Eye-safe 1.55 μm passively Q-switched Er,Yb:GdAl3(BO3)4 diode-pumped laser.

We report for the first time, to the best of our knowledge, on a diode-pumped passively Q-switched Er,Yb:GdAl3(BO3)4 laser. By using a Co2+:MgAl2O4 crystal as a saturable absorber, Q-switched laser pulses with a duration of 12 ns and a maximum energy of 18.7 μJ at a repetition rate of 32 kHz corresponding to an average output power of 0.

Dispersion and anisotropy of thermo-optic coefficients in tetragonal GdVO(4) and YVO(4) laser host crystals: erratum.

We addressed errors found in our measurements of thermo-optic coefficients and thermal coefficients of the optical path (TCOP) in tetragonal vanadates, YVO(4) and GdVO(4) [Appl. Opt.52, 698 (2013)].

200 kHz 5.5 W Yb(3+): YVO4-based chirped-pulse regenerative amplifier.

A chirped-pulse regenerative amplifier based on a Yb:YVO4 (Yb:YVO) crystal was demonstrated for the first time, to our knowledge. A novel wavelength-independent off-axis technique was used to deliver 26.6 W of pump power with a low quantum defect.

High-power, efficient, semiconductor saturable absorber mode-locked Yb:KGW bulk laser.

A high-power, diode-pumped, semiconductor saturable absorber mode-locked Yb(5%):KGW bulk laser was demonstrated with high optical-to-optical efficiency. Average output power as high as 8.8 W with optical-to-optical efficiency of 37.

In-band-pumped Ho:KLu(WO4)2 microchip laser with 84% slope efficiency.

We report on a continuous-wave Ho:KLu(WO4)2 (KLuW) microchip laser with a record slope efficiency of 84%, the highest value among the holmium inband-pumped lasers, delivering 201 mW output power at 2105 nm. The Ho laser operating at room temperature on the (5)I8→(5)I7 transition is in-band-pumped by a diode-pumped Tm:KLuW microchip laser at 1946 nm. Ho:KLuW laser operation at 2061 and 2079 nm is also demonstrated with a maximum slope efficiency of 79%.

Microchip laser operation of Tm,Ho:KLu(WO₄)₂ crystal.

A microchip laser is realized on the basis of a monoclinic Tm,Ho-codoped KLu(WO₄)₂crystal cut for light propagation along the Ng optical indicatrix axis. This crystal cut provides positive thermal lens with extremely weak astigmatism, S/M = 4%. High sensitivity factors, M = dD/dP(abs), of 24.

Diode-pumped microchip Tm:KLu(WO₄)₂ laser with more than 3 W of output power.

A diode-pumped microchip laser containing a quasi-monolithic plano-plano cavity is realized on the basis of a Tm:KLu(WO₄)₂ crystal. The maximum CW output power is 3.2 W (at an absorbed pump power of 6.

Highly efficient 12 W diode-pumped actively Q-switched Yb:KGd(WO4)2 laser.

A compact diode-pumped actively Q-switched Yb:KGW laser is demonstrated with an optical-to-optical efficiency of 50%. In a 3-mirror laser cavity configuration output power of 12.2 W with repetition rate up to 50 kHz and pulse duration of 10-24 ns was obtained.

Efficient diode-pumped Tm:KYW 1.9-μm microchip laser with 1 W cw output power.

We report on a diode-pumped Tm:KYW microchip laser generating 1 W continuous-wave output power. The laser operates at a wavelength of 1.94 μm in the fundamental TEM(00) mode with 71% slope efficiency relative to the absorbed pump radiation and 59% slope efficiency relative to the incident pump radiation.

Highly efficient continuous-wave diode-pumped Er, Yb:GdAl3(BO3)4 laser.

We report the highly efficient continuous-wave diode-pumped laser operation of Er, Yb:GdAl3(BO3)4 crystal. Absorption and stimulated emission spectra, emission lifetimes, and efficiencies of energy transfer from Yb3+ to Er3+ ions were determined. A maximal output power of 780 mW was obtained at 1531 nm at absorbed pump power of 4 W with slope efficiency of 26%.

High average power 1314 nm Nd:YLF laser, passively Q-switched with V:YAG.

A 1314 nm Nd:YLF laser was designed and operated both CW and passively Q-switched. Maximum CW output of 10.4 W resulted from 45.

Dispersion and anisotropy of thermo-optic coefficients in tetragonal GdVO4 and YVO4 laser host crystals.

A detailed experimental study of dispersion and anisotropy of thermo-optic coefficients dn/dT and thermal coefficients of the optical path W=dn/dT+(n-1)α is performed for tetragonal YVO(4) and GdVO(4) laser host crystals by a laser beam deviation method. It is supported by theoretical description of thermo-optic effects, taking into account the volumetric thermal expansion effect and the temperature dependence of electronic bandgap E(g). Linear thermal expansion coefficients α were also determined by a dilatometric technique.

Passively Q-switched microchip Er, Yb:YAl3(BO3)4 diode-pumped laser.

We report, for the first time to our knowledge, a diode-pumped cw and passively Q-switched microchip Er, Yb:YAl(3)(BO(3))(4) laser. A maximal output power of 800 mW at 1602 nm in the cw regime was obtained at an absorbed pump power of 7.7 W.

Thermo-optic coefficients study in KGd(WO4)2 and KY(WO4)2 by a modified minimum deviation method.

Thermo-optic coefficients anisotropy was characterized in monoclinic potassium (rare-earth) double tungstates KGd(WO4)2 and KY(WO4)2 in the spectral range of 0.44-0.63 μm by a modified minimum deviation method.