Nonlinear Optical Crystals: A Complete Survey

The primary goal of this review is to present a clear chemical perspective of borates in order to stimulate and facilitate the discovery of new borate-based optical materials. These materials, whic...

Borates: A Rich Source for Optical Materials.

Efficient self-Raman frequency conversion from a diode-pumped actively Q-switched Nd:YVO4 laser at 1064 nm to Stokes emission at 1176 nm is achieved for the first time to the author’s knowledge. With a 0.2-at. % Nd:YVO4 crystal, greater than 1.5 W of power at a wavelength of 1176 nm at a repetition rate of 20 kHz was generated with a diode pump power of 10.8 W, corresponding to a conversion of 13.9%. Pulse width and peak power were 18 ns and 4.2 kW, respectively.

High-power diode-pumped actively Q-switched Nd:YVO4 self-Raman laser: influence of dopant concentration.

We report on the first passively Q-switched Nd:YAlO3 laser at ~1079.5 nm using MoS2 as saturable absorber. The MoS2 saturable absorber is fabricated by transferring the liquid-phase-exfoliated MoS2 nanosheets onto a BK7 glass substrate. By inserting the glass MoS2 saturable absorber into a plano-concave Nd:YAlO3 laser cavity, we obtain a stable Q-switched laser operation with a maximum average output power of 0.26 W corresponding to a pulse repetition rate of 232.5 kHz, a pulse width of 227 ns and a pulse energy of about 1.11 μJ. The results experimentally confirm the promising application of the new kind of 2D material, few-layer MoS2, in solid state lasers.

Passively Q-switched Nd:YAlO_3 nanosecond laser using MoS_2 as saturable absorber

The semi-organic single crystal of potassium 3,5-dinitrobenzoate (KDNB) was successfully grown by slow evaporation solution technique (SEST) at room temperature. The lattice parameters of the grown KDNB crystal were confirmed by single crystal X-ray diffraction. The functional groups of the KDNB crystal were confirmed by Fourier transform infrared (FTIR) spectroscopy analysis. The optical quality of the grown crystal was identified by UV-Vis NIR spectral analysis. The grown crystal has good optical transparency in the range of 410–1100 nm. In the photoluminescence spectrum, sharp broad emission peaks were observed, which indicate violet and blue emission. The photoconductivity study reveals that the grown crystal has a negative photoconductive nature. The thermal behaviour of the crystal has been investigated by thermogravimetric and differential thermal analysis (TG-DTA). Vickers microhardness analysis was carried out to identify the mechanical stability of the grown crystal and the indentation size effect (ISE) was explained satisfactorily by Hays–Kendall's approach and proportional specimen resistance model [PSRM]. A chemical etching study was carried out and the etch pit density (EPD) was calculated. Laser damage threshold (LDT) energy has been measured by using a Nd:YAG laser (1064 nm). The dielectric permittivity and dielectric loss as a function of frequency were measured for the grown crystal. The solid state properties such as plasma energy, Penn gap and Fermi energy were evaluated for the KDNB crystal using the empirical relation. These estimated values were utilized to report the electronic polarizability. This matches well to the value calculated from Clausius–Mossotti relation, Lorentz–Lorentz equation, optical band gap energy and coupled dipole method (CDM). The third-order nonlinear optical properties such as refractive index (n2), absorption co-efficient (β) and susceptibility (χ(3)) were studied using Z-scan technique at 632.8 nm of He–Ne laser.

Growth and characterization of semi-organic third order nonlinear optical (NLO) potassium 3,5-dinitrobenzoate (KDNB) single crystals

A diode-pumped highly efficient Cr4+:YAG passively Q-switched Nd:GdVO4 laser formed by a plano–concave resonator has been demonstrated. At the highest attainable absorbed pump power of 11.4 W, 4.05 W of average output power, which was two thirds of the maximum corresponding cw output, was achieved with an optical conversion efficiency of 35.5%, and the slope efficiency was determined to be 46.8%, reaching 85% of the magnitude of its cw counterpart. The resulting shortest pulse duration, single-pulse energy, and peak power were found to be 13 ns, 90 μJ, and 7 kW, respectively, with a pulse repetition frequency (PRF) of 45 kHz. Two particularly modified resonator configurations were employed; the largest pulse energy and the highest peak power reached were, respectively, 154 μJ and 11.2 kW at 8.5 W of absorbed pump power. An analytical relation between the PRF and the absorbed pump power is given for a passively Q-switched laser, showing good consistency with experiment with a Nd:GdVO4 laser. The dependence of the operational parameters on the pump power and on the output coupling was also investigated experimentally. Issues involving the criterion for passive Q switching are discussed in some detail for Cr4+:YAG passively Q-switched neodymium-doped vanadate lasers.

Efficient passive Q-switching operation of a diode-pumped Nd:GdVO 4 laser with a Cr 4+ :YAG saturable absorber

Efficient second harmonic generation of pulsed laser radiation in BiB3O6 (BIBO) crystal with different phase matching directions

The absorption spectra of the 0.5at.% and 1at.% Co: LaMgAl11O19 (LaMg1-xCoxAl11O19, x=0.005 and 0.01, abbreviated as Co:LMA) crystals were measured at room temperature, and the results show that the Co: LMA crystals have two absorption bands, and the absorption band located at 1030–1660 nm can be used for a passive saturable absorber Q switch of 1.3–1.6µm laser. The passive pulsed laser output of LD-end-pumped Nd:GdVO4 1.34µm laser was demonstrated for the first time by using the 0.5 at.% Co:LMA crystal as a saturable absorber Q switch. The maximum average output power of 500 mW was obtained under the pumping power of 25 W. The shortest pulse width, the largest pulse energy and the highest peak power were obtained to be 160 ns, 25.5µJ and 150 W, respectively.

Chenlin Du

Papers

Efficient passive Q-switching operation of a diode-pumped Nd:GdVO 4 laser with a Cr 4+ :YAG saturable absorber

Efficient second harmonic generation of pulsed laser radiation in BiB3O6 (BIBO) crystal with different phase matching directions

Pulsed laser output of LD-end-pumped 1.34 μm Nd: GdVO4 laser with Co: LaMgAl11O19 crystal as saturable absorber

High-power actively Q-switched Nd:GdVO4 laser end-pumped by a fiber-coupled diode-laser array

Growth of new laser crystal Nd:LuVO4 by the Czochralski method