The present work gives a brief review of the nonlinear χ⁽²⁾- and χ⁽³⁾-lasing properties of SRS-active natural crystals (minerals) known so far. This compilation complements new results of a detailed investigation of Raman induced χ⁽³⁾-effects in aragonite single crystals (orthorhombic CaCO₃) under single- and dual-wavelength picosecond excitation in the UV, visible and near-IR spectral ranges. The studied effects at room and cryogenic temperatures comprise Stokes and anti-Stokes combs of almost two octaves bandwidth, THG, SFG, as well as cascaded and cross-cascaded χ⁽³⁾ ↔ χ⁽³⁾ interactions. All recorded lasing χ⁽³⁾-components were identified and attributed to three observed SRS-promoting vibration modes ω_{SRS 1} ≈ 1087 cm^–1, ω_{SRS 2} ≈ 152 cm^–1, and ω_{SRS 3} ≈ 205 cm^–1 (at room temperature) of aragonite. Stimulated Raman scattering (SRS) investigations of minerals so far enrich the arsenal of SRS-active crystals, which can be applied to solve fundamental and applied tasks of modern laser physics and nonlinear optics. (© 2012 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) (© 2011 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)

Spectroscopic properties and continuous-wave laser performance of a new Yb_0.015:Lu_0.162Gd_0.823VO₄ mixed vanadate crystal are reported. An appreciable discontinuous increase in output power occurs during the σ - to π -polarization switching process in the laser oscillation. A maximum output power of 4.3 W is generated with an optical-to-optical efficiency of 46%, whereas the average slope efficiency is determined to be 73–77%, depending on the output coupling utilized. (© 2012 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) (© 2011 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)

A compact diode-pumped solid-state Tm:KY(WO₄)₂ laser with cavity length of 1 cm passively Q-switched with a PbS-quantum-dot-based saturable absorber is presented. The laser operates at the wavelength of 1.94 µm and produces pulses with duration of 8 ns and energy of 30 µJ at the repetition rate up to 4.2 kHz. The maximum output power of 120 mW is achieved at incident pump power of 1.15 W. (© 2012 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) (© 2011 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)

Intra-cavity frequency doubling of continuous-wave (CW) laser emission on the quasi-three level (⁴F_3/2 → ⁴I_9/2) laser transition of Nd³⁺ in Nd:GGG is reported by using a three-mirror folded resonator. The thermal lens experienced by the optically-pumped Nd:GGG laser crystal is measured as a function of the absorbed pump power and compared to that found, in the same conditions, in the case of Nd:YAG. Results are interpreted by using a simple model accounting for the absorbed pump power and the thermo-mechanical properties of each laser crystal. Diode-pumped blue laser operation is achieved, for the first time, at 467.0 and 468.5 nm with output powers of 230 and 450 mW, respectively. Simultaneous laser operation resulting both from frequency-doubling and frequency summing at the three 467.1, 467.7, and 468.1 nm laser wavelengths is also obtained with a total output power of 60 mW. (© 2012 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) (© 2011 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)

The characterization of new gain-switched Fe:Cr:Zn_1–xMg_xSe laser working at the room temperature and its comparison to Fe:ZnSe laser was performed. The laser oscillation behavior, generation efficiency and output wavelength tuning possibilities were demonstrated. It was shown that the absorption and luminescence spectra of Fe:Cr:ZnMgSe crystal are shifted towards longer wavelengths in comparison with Fe:ZnSe active material. The difference is approximately 300 nm and it corresponds to measured absorption and emission spectra. The maximal Fe:Cr:ZnMgSe laser generated energy and the slope efficiency with respect to the absorbed energy were 200 µJ and 4.5%, respectively. (© 2012 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) (© 2011 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)

Multiple Stokes and anti-Stokes χ⁽³⁾-nonlinear generation in the tetragonal crystal of CaYAlO₄ was observed at 300K and ≈9K under picosecond excitation in the visible spectral range. All the recorded Raman induced laser lines were identified and attributed to the SRS-promoting vibration mode of octahedral [AlO₆]^–9 units of the crystal. (© 2012 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) (© 2011 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)

In this work it is shown, that laser with injection of reflected radiation can possess the high longitudinal spatial selectivity. Laser figures here both the emitter and the detector of radiation. This attribute, having volumetric character for laser fields, can be considered as a new modality in optical microscopy. Using the experimental possibilities we achieved the spatial resolution at a level of several microns. The optimization of laser sources is to lead to longitudinal spatial resolution at a level of nanometers. (© 2012 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) (© 2011 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)

We presented the rapid diagnostic test for dengue infection based on light spectrum of human blood. The transmission spectra of dengue infected whole blood samples have been recorded in ultra violet to near infrared range (400–800 nm) of about 30 conformed infected patients and compared to normal blood samples. Transmission spectra of dengue infected blood illustrate a strong band from 400–600 nm with prominant peaks at 540 and 580 nm, where is in case of normal blood below 600 nm, total absorption has been observed. These prominent peaks from 400–600 nm are characteristics of cells damage and dangue virus antibodies immunoglobulin G (IgG) and immunoglobulin M (IgM) produced against dengue antigen. The presented diagnostic method is non invasive, cost effective, easy and fast screening technique for dengue infected patients. (© 2012 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) (© 2011 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)

In combination with morphological evaluation tests, we employ Raman spectroscopy to select higher potential reproductive embryos during in vitro fertilization (IVF) based on chemical composition of embryos culture medium. In this study, 57 Raman spectra are acquired from both higher and lower quality embryos culture medium (ECM) from 10 patients which have been preliminarily confirmed by clinical assay. Data are fit by using a linear combination model of least squares method in which 12 basis spectra represent the chemical features of ECM. The final fitting coefficients provide insight into the chemical compositions of culture medium samples and are subsequently used as criterion to evaluate the quality of embryos. The relative fitting coefficients ratios of sodium pyruvate/albumin and phenylalanine/albumin seem act as key roles in the embryo screening, attaining 85.7% accuracy in comparison with clinical pregnancy. The good results demonstrate that Raman spectroscopy therefore is an important candidate for an accurate and noninvasive screening of higher quality embryos, which potentially decrease the time-consuming clinical trials during IVF. (© 2012 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) (© 2011 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)