Parametric Generation Of Light Research Articles

Non-destructive periodic poling quality evaluation of MgO:PPLN and Rb:PPKTP crystals based on crystal translation and parametric light generation

The work discloses a flexible, non-destructive, aberration-free, and automated periodic poling quality evaluation technique of the periodically poled crystals in the whole volume of the crystal with very high control and resolution. The method is based on a crystal translation in the directions perpendicular to the pump laser beam and the simultaneous recording of the parametric signal conversion efficiency in a simple single-pass parametric light generator setup. This technique allowed us to investigate and quantitatively describe the ferroelectric domain structure homogeneity of the periodically poled lithium niobate and potassium titanyl phosphate crystals with single, multi, and fan-out grating designs and offers a practicable overall efficiency assessment of the quasi-phase-matched device.

Optical bistability in layered InSe crystal

In this study, we experimentally study the dependence of the intensity of laser radiation incident on and transmitted through a layered InSe crystal. A picosecond YAG:Nd3+ laser with a parametric light generator was used as a light source, making it possible to generate light pulses with a duration of [Formula: see text]30 ps, tunable in frequency within the range of 0.75–1.5 μm. Optical bistability in the region of exciton resonance was detected in an InSe crystal at room-temperature under the picosecond YAG:Nd laser. It is shown that the decrease in absorption in the exciton resonance region is associated with the process of exciton–exciton interaction, shielding of excitons, and the Mott transition.

Asymmetric parametric generation of images with nonlinear dielectric metasurfaces

Subwavelength dielectric resonators assembled into metasurfaces have become a versatile tool for miniaturising optical components approaching the nanoscale. An important class of metasurface functionalities is associated with asymmetry in both generation and transmission of light with respect to reversals of the positions of emitters and receivers. Nonlinear light-matter interaction in metasurfaces offers a promising pathway towards miniaturisation of the asymmetric control of light. Here we demonstrate asymmetric parametric generation of light in nonlinear metasurfaces. We assemble dissimilar nonlinear dielectric resonators into translucent metasurfaces that produce images in the visible spectral range being illuminated by infrared radiation. By design, the metasurfaces produce different and completely independent images for the reversed direction of illumination, that is when the positions of the infrared emitter and the visible light receiver are exchanged. Nonlinearity-enabled asymmetric control of light by subwavelength resonators paves the way towards novel nanophotonic components via dense integration of large quantities of nonlinear resonators into compact metasurface designs.

Nonlinear crystals for parametric light generation in the near and middle IR range

A review and comparative analysis of nonlinear optical crystals with a wide transparency range is presented. The conclusion is made about the possibility of creating on their basis highly efficient parametric light generators in the middle and far infrared range for lidar systems.

Оптимизация спектральных и геометрических параметров параметрического генератора света среднего ИК-диапазона

The results of computational and experimental studies of the parameters of a parametric light generator in the mid-IR range are presented. One of the main problems of OPO in the near and mid-IR range (1-8 μm) is the high divergence of the output radiation. The purpose of this study is to improve the spectral and amplitude-spatial characteristics for the out-of-cavity scheme of the IR-OPO ring resona-tor. In an in vitro experiment simulating the radiation of an IR parametric laser, the dependences of the spectral width and quality factor of the radiation of a tunable laser frequency on the wavelength were obtained. It is shown that the improved optical-geometrical parameters of the out-of-zone OPO scheme made it possible to achieve high values of the spectral radiation width (≤ 1 cm-1) and quality factor (≥ 4.106). It is shown that such a developed scheme of an out-of-cavity OPO based on new chalcogenide crystals will expand its application in the mid- and far-IR ranges.

The Yb3+:LuAlO3 crystal as an active medium for picosecond mode-locked lasers

Herein, we report on the mathematical modelling and experimental study of the regime of nonsoliton mode locking in a laser based on the Yb3+:LuAlO3 (Yb:LuAP) crystal with longitudinal pumping by laser diode radiation. Simulation based on the Haus master equation permitted to determine the requirements for the parameters of a saturable absorber (SA), the level of the average output power, the size of the TEM00 mode of the cavity in the active element and on the gate to obtain a stable regime of generation of picosecond laser pulses. Laser experiments were carried out in a fourmirror X-shaped resonator using a semiconductor saturable mirror (SESAM) as a passive modulator and a laser diode with a fiber output of a maximum power up to 30 W at a wavelength of 978.5 nm as a pump source. We obtained a stable passive mode locking with a maximum average output power of up to 12 W and an ultrashort pulse duration of about 2 ps at an optical conversion efficiency of pump radiation into lasing radiation of about 38 %. Laser pulses were obtained at a central wavelength of about 999 nm with a minimum Stokes shift (about 2 %) with respect to the pump radiation, which significantly reduced the thermal load on the active element. Additionally, the preliminary results on the second harmonic generation and synchronous pumping of a parametric light generator using a Yb3+ : LuAlO3 crystal laser as a pump source are presented.

Influence of growth temperature of KTiOAsO4 single crystals on their physicochemical parameters and formation of domain structures

A potassium titanyl arsenate (KTiOAsO4, KTA) crystal 50 × 80 × 60 mm in size has been grown by upgraded Czochralski method from flux (TGGS) with a decrease in temperature from 900 to 770 °C during pulling. It is shown that the spectroscopic properties of the parts of KTA crystals grown at 900 and 770 °C are close, whereas the electrical conductivity of the low-temperature (770 °C) KTA part turned out to be an order of magnitude lower than that of the high-temperature part. Visualisation of the domain structure by second-harmonic generation microscopy revealed a more efficient domain intergrowth (throughout the sample) in the low-temperature KTA, which is important for forming a regular domain structure (RDS) in a KTA-based nonlinear optical element. It is established that the quantum efficiency of parametric generation of light in the RDS formed in low-temperature KTA is several times higher than in the case of high-temperature KTA. The results obtained are important for optimising RDS parameters.

Broadband tunable source of mid-IR laser radiation for photoacoustic spectroscopy

Control over volatile products of metabolic processes in human body in exhaled air is a promising method for noninvasive medical diagnostics. The mid-IR range (2–12 μm) is of great interest for diagnostic applications of the exhaled air spectral analysis. Laser optoacoustic spectroscopy is quite attractive for detecting a large set of gaseous substances; however, high-power sources of tunable radiation are required to increase the method sensitivity. We consider the possibility of using a parametric light generator based on a BaGa4Se7 crystal as a broadband tunable mid-IR laser source for laser optoacoustic spectroscopy.

The Induced Absorption of Photorefractive Crystals BSO

This study aims to calculate the induced absorption coefficient in the photorefractive crystals (Bi12 SiO20). A theoretical model was proposed and by using mathcad14 program the results were obtained .The average of induced absorption coefficient (α) was highest at (420 cm-1). Through using the proposed program, the induced absorption coefficient was found theoretically then compared with the experimental results through different situations. The exciting wavelengths of laser were 530, 500mm. It is noticed that the practical results conforms with the theoretical ones. The induced absorption coefficient increases with the increasing the applied powers. Practically, different laser rays of various wavelength have been focused on the crystal BSO. The spectrometer was used to get the spectrum of each wavelength and then the spectrum of crystal was found without radiation . Using a laser generator (Parametric light generator LТ-2215), different wavelengths were obtained (520, 530, 545, 580, 590, 600) nm. The induced absorption coefficient increases when the exciting wavelength decreases, where the influential wavelength was 520nm. http://dx.doi.org/10.31257/2018/JKP/100202

Study of the possibility of using a parametric-light-generator-based laser system for lidar probing of the composition of the atmosphere

This paper discusses the possibility of using a laser system with parametric light generation based on a nonlinear KTiOAsO4 crystal for lidar probing of the atmosphere in the 3–4 μm range. A combined technique has been developed for lidar measurements of the gaseous components of the atmosphere, using the differential-absorption method (DAM) and differential optical absorption spectroscopy (DOAS). The DAM–DOAS technique has been tested in a numerical experiment to estimate the possibilities of lidar probing of minor gaseous components of the atmosphere.

Application of Optical Parametric Generator for Lidar Sensing of Minor Gas Components of the Atmosphere in 3–4 μm Spectral Range

Possibility of application of a laser system with parametric light generation based on a nonlinear KTA crystal for lidar sensing of the atmosphere in the 3–4 μm spectral range is investigated. A technique for lidar measurements of gas components in the atmosphere with the use of differential absorption lidar (DIAL) and differential optical absorption spectroscopy (DOAS) method is developed. The DIAL-DOAS technique is tested for estimating the possibility of laser sensing of minor gas components in the atmosphere.

Parametric generation of light in a cavity: An analytical approximation

A new analytical approximate solution is suggested for the problem of nonlinear parametric generation of light in a cavity. This solution is much more accurate than the known ones. Two- and three-cavity lasing schemes are considered and criteria for their adequacy are ascertained. The accuracy of the results is confirmed by computer simulation.

On the theory of parametric light generation

A theory of parametric light generation in a resonator with dissipative losses is presented. Approximate analytical solutions are obtained for schemes with two and three resonating waves and their adequacy criteria are formulated. Computer simulation confirmed the accuracy of the analytical solutions.

8.5 W mode-locked Yb:Lu1.5Y1.5Al5O12 laser with master oscillator power amplifiers.

We report on a diode-pumped passively mode-locked Yb:Lu(1.5)Y(1.5)Al(5)O(12) (Yb:LuYAG) laser for the first time to our knowledge. With the mixed crystal of Yb:LuYAG as gain medium, the mode-locked laser generated 2.2 W of average output power with a repetition rate of 83.9 MHz and pulse duration of 2.4 ps at the wavelength of 1030 nm. In order to obtain higher output power, the output from the mode-locked oscillator was further amplified to 8.5 W by two-stage single-pass amplifiers. The high-power picosecond laser is very useful for applications such as pumping of midinfrared optical parametric oscillators, material microprocessing, and UV light generation.

Parametric generation of high frequency coherent light in negative index materials and materials with strong anomalous dispersion

AbstractWe demonstrate the possibility of generation of coherent radiation with tunable frequencies higher than the frequency of the driving field v

Medical applications of mid-IR lasers Problems and prospects

Any application of lasers in medicine is based on a compromise between the efficiency with which the laser radiation interacts with biological tissue and the concomitant collateral effects. Correspondingly, parameters minimizing undesirable damage to tissue must be determined. The development of a new generation of solid-state lasers tunable over a wide range in the mid-IR range of the spectrum with parametric generation of light and a combination of high radiation intensity and relatively low pulse energy at high repetition frequency opens up new possibilities for less-invasive, high-precision, laser surgery, first and foremost, in ophthamology and neuro- and cardiosurgery.

A method of optical implementation of frequency encoded all optical logic gates based on multiphoton processes in non linear material

A novel frequency encoded all optical logic gates are proposed exploiting multiphoton processes in non linear optical medium. In the frequency encoding of the information the ‘0’ is represented by a frequency ω and ‘1’ is represented by another frequency 2ω. The gates proposed are NOT, OR, AND, NAND and NOR among which NAND and NOR are universal. Using these gates one can generate other important gates and logical function generating all optical devices. Two main three-photon processes, second harmonic generation (SHG) and parametric light generation (PLG) are used to implement the gates and the corresponding appropriate non linear material is LiB3O5 (LBO) which has wide operating and transparency range in the wavelength 350–3,200 nm. The source of optical frequency encoded signal may be derived from an external cavity diode laser generating a wavelength 1,560 nm for ω (‘0’ state of information) and its second harmonic 780 nm for 2ω (‘1’ state of information).

Simulation of backward light waves generated in isotropic optical waveguides

The existing coherent light sources are nonuniformly distributed by frequency in the optical range. Thus, work toward the development of tunable lasers operating in the middle IR range has long been underway. Nevertheless, the region 4–8 µm has been poorly mastered, and more longwave lasers have too narrow frequency tuning ranges. One way of solving these problems is to harness the effect of parametric light generation whose special case is parametric generation of backward light waves in nonlinear optical media, which is the subject of the present work.

Parametric generation of light X waves by Bessel beam pump

Spatial and temporal localization of light energy is of great importance for various applications. The diffraction-free and dispersion-free propagation of pulsed beams (usually called as X waves) can be achieved both in linear [1–3] and nonlinear media. In a quadratic medium X waves are formed spontaneously through a trigger mechanism of conical emission via mismatched second harmonic generation [4–9]. An appearance of conical emission is a result of noncollinear interactions which are strictly controlled by phase matching conditions of different components of spatial-temporal spectrum of the waves. It was demonstrated that angular dispersion of the waves excited in optical parametric generator (OPG) by quasimonochromatic plane pump wave corresponds to angular dispersion of X waves [10, 11]. In this paper we reveal an existence of different X wave modes in OPG pumped by quasimonochromatic Bessel beam. An X wave can be represented as a superposition of Bessel beams, the frequencies ω, wave vectors k, and half-cone angles ψ of which are related in dispersive medium by an equation

Numerical simulation and experimental investigation of parametric generation of light pulses in a KTP crystal

Numerical simulation and experimental investigation of the process of parametric generation of light inside a KTP crystal excited by laser pulses have been performed. The calculation method includes the solution of a system of coupled truncated equations, which describe the three-wave interaction in a laser resonator partially filled with a KTP crystal, with the use of reflection boundary conditions for amplitudes together with initial conditions corresponding to the level of noises. The time profile of the intensities of the interacting pulses and their energies were calculated. The results obtained make it possible to determine the optimal values of optical parameters of the resonator that ensure the maximum efficiency of conversion. The calculated values of the conversion efficiency are in good agreement with experimental data.