Operation of an all solid-state compact pulsed Raman laser pumped by a continuous-wave laser diode is demonstrated. The Stokes and anti-Stokes radiations of stimulated Raman scattering at the 1.181 and 0.973 μm wavelengths, respectively, are generated as a result of self-frequency conversion of the 1.067 μm laser radiation in a Nd3+:KGd(WO4)2 crystal. With Q-switched operation, the Raman laser threshold corresponds to 230 mW of a laser diode light power. The output power of 4.8 mW is achieved at the Stokes wavelength with a kilohertz repetition rate.
A neutronographic study is made of magnetic structure and spin‐orientational transitions in polycrystalline samples of the system BaCo2−xZnxFe16O27 (Co2−xZnxW). Along with this studies measurements of the macroscopic magnetic characteristics, X‐ray dilatometry, and DTA are performed. The diagram of the magnetic state is plotted in the coordinates: content‐temperature. The compounds with Zn2+ ion content, 0 ≦ x ≦ 1.6 exhibit the sequence of orientational phase transitions coneplane‐cone‐axis of easy magnitization when the temperature increases. The order of these transitions is determined and the role of Co2+ ions for creation of planar anisotropy in oxide ferrimagnetics with hexagonal structure is discussed.
A system of radiative transfer equations is used to calculate the loss coefficient for amplified luminescence fluxes propagating along and transverse to the cavity axis in the active layer of high-power laser diode arrays taking the spreading of charge carriers in the cladding and contact layers of InGaAs/GaAs/AlGaAs heterostructures into account. It is shown that the spreading of charge carriers leads to a significant change in the amplified luminescence flux which can contribute up to 18% to the lasing threshold of these laser diode arrays. The calculated loss coefficients can greatly simplify the determination of the amplified luminescence fluxes in laser diode arrays with an error of less that 16% and can be used to determine how much the amplified luminescence affects the power and dynamic characteristics of diode arrays.Introduction. High-power laser diode arrays (LDAs) are coming into ever wide use as compact, highly efficient sources of optical excitation for solid state lasers [1][2][3]. Reducing the energy demand by these emitters requires optimization of the parameters of the LDAs, as well as of the solid state lasers. The power of modern LDAs used as pumps is approaching 80-150 W [1, 4]. These relatively high LDA powers have been achieved by substantial increase in the length of the cavities and the total widths of the heterostructure lasing elements. In most cases of practical interest, the LDA is characterized by a relatively high area of the active layer of the laser heterostucture. Thus, it is to be expected that, in accordance with [5-10], intense fluxes of amplified luminescence should develop in the active layers of LDAs; these result in an increase in the threshold and a reduction in the laser output power. It has been shown [5, 6, 8-10] that the AL fluxes for single laser diodes (with a single emitting region, or strip contact) can be analyzed by introducing an AL loss coefficient α lum determined from the balance between emission, amplification, and absorption of spontaneous emission ]11]. The value of α lum depends on many factors, in particular, on the composition of the active layer, the geometry of the laser structure, the excitation conditions, etc. Thus, as opposed to the loss coefficient for the laser emission, finding α lum is a rather complicated task in most cases of practical importance. This paper deals with the determination of the loss coefficient for AL produced in the active layer of highpower LDAs with as many as a few hundred regions. The resulting values of α lum can be used to estimate how much AL affects the threshold, dynamic, and power properties of LDAs and to determine methods for further improvement in the characteristics of LDAs and of diode pumped solid state lasers.Propagation of Fluxes of Amplified Luminescence in LDAs. The AL characteristics of concern for the parameters of LDAs (output wavelengths 940-980 nm) used to pump solid state erbium lasers are studied here. These LDAs are generally based on InGaAs/GaAs/AlGaAs heterostructures with two quantum-dimension...
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