Optimization of Yb:YAG/Cr(4+):YAG composite ceramics passively Q-switched microchip lasers

Program for New Century Excellent Talents in University (NCET) [NCET-09-0669]; Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (SRF for ROCS, SEM); Ph.D. Programs Foundation of Ministry of Education of CThe laser characteristics of laser-diode end-pumped Yb:YAG/Cr4+:YAG composite ceramics microchip passively Q-switched lasers were studied by solving the coupled rate equations numerically taking into account the reabsorption of Yb:YAG ceramics at laser wavelength. Effects of the reflectivity of the output coupler, the concentrations and thickness of the saturable absorbers, and pump beam area on the laser performance were investigated analytically. The simulation results of the Yb:YAG/Cr4+:YAG composite ceramics passively Q-switched microchip lasers were in good agreement with the experimental data. Better laser performance (high peak power, short pulse width and good optical-to-optical efficiency) of the composite Yb:YAG/Cr4+:YAG ceramics passively Q-switched laser can be obtained by using a thin Cr4+:YAG ceramic with high concentration, suitable reflectivity of the output coupler and proper pump beam diameter under high pump power intensity according to our simulations

Enhancement of Cr, Yb:YAG self-Q-switched lasers by bonding Yb:YAG crystal

Conference Name:2011 International Quantum Electronics Conference, IQEC 2011 and Conference on Lasers and Electro-Optics, CLEO Pacific Rim 2011. Conference Address: Sydney, NSW, Australia. Time:August 28, 2011 - September 1, 2011.Australian National University (ANU); Macquarie University, MQ Photonics Research Centre; The University of Sydney, School of Physics; The University of Queensland (UQ); Griffith UniversityEfficient laser-diode pumped Cr, Yb:YAG self-Q-switched laser by bonding Yb:YAG crystal to enhance inversion population have been demonstrated for the first time. Average output power of 1 W and optical-to-optical efficiency of 18.5% have been achieved. ? 2011 IEEE

Generation of Ince-Gaussian beams in highly efficient, nanosecond Cr, Nd:YAG microchip lasers

Program for New Century Excellent Talents in University (NCET) [NCET-09-0669]; Fundamental Research Funds for the Central Universities [2010121058]; PhD Programs Foundation of the Ministry of Education of China [20100121120019]; Russian Foundation for Basic Research; Program of the Presidium of Russian Academy of Sciences 'Extreme laser fields and their applications'Direct generation of higher-order Ince-Gaussian (IG) beams from laser-diode end-pumped Cr, Nd:YAG self-Q-switched microchip lasers was achieved with high efficiency and high repetition rate. An average output power of over 2 W was obtained at an absorbed pump power of 8.2 W; a corresponding optical-to-optical efficiency of 25% was achieved. Various IG modes with nanosecond pulse width and peak power of over 2 kW were obtained in laser-diode pumped Cr, Nd:YAG microchip lasers under different pump power levels by applying a tilted, large area pump beam. The effect of the inversion population distribution induced by the tilted pump beam and nonlinear absorption of Cr4+-ions for different pump power levels on the oscillation of higher-order IG modes in Cr, Nd:YAG microchip lasers is addressed. The higher-order IG mode oscillation has a great influence on the laser performance of Cr, Nd:YAG microchip lasers

Comparative study on enhancement of self-Q-switched Cr,Yb:YAG lasers by bonding Yb:YAG ceramic and crystal

Program for New Century Excellent Talents in University (NCET) [NCET-09-0669]; Fundamental Research Funds for the Central Universities [2010121058]; Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (SRF fEnhancement of laser-diode pumped self-Qswitched Cr, Ca, and Yb3+ ions co-doped YAG (Cr,Yb:YAG) lasers by bonding Yb:YAG ceramic to increase pump power absorption efficiency have been demonstrated for the first time to our best knowledge. Efficient Cr,Yb:YAG self-Q-switched laser performance has been achieved by bonding Yb:YAG ceramic. The effect of transmission of output coupler (TOC) on the laser performance has been investigated and found that the best laser performance was achieved with TOC = 20% for Yb:YAG ceramic. Slope efficiency of 20% was achieved with TOC = 20% for Cr,Yb:YAG self-Q-switched laser by bonding Yb:YAG ceramic. Maximum average output power of 683 mW was measured at absorbed pump power of 4.5 W; the corresponding optical-to-optical efficiency is 15.2%. The output laser pulse characteristics were compared for Cr,Yb:YAG self-Q-switched lasers by bonding Yb:YAG ceramic and crystal under different transmission of output coupler. For the same TOC, the laser performance of Cr,Yb:YAG self-Q-switched lasers by bonding Yb:YAG ceramic is better than that by bonding Yb:YAG crystal. (C) 2011 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGa

Efficient, nanosecond self-Q-switched Cr,Yb:YAG lasers by bonding Yb:YAG crystal

Program for New Century Excellent Talents in University (NCET) [NCET-09-0669]; Fundamental Research Funds for the Central Universities [2010121058]; Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (SRF fEfficient laser-diode pumped self-Q-switched Cr,Yb:YAG lasers by bonding Yb:YAG crystal to increase pump power absorption efficiency have been demonstrated for the first time to our best knowledge. The effect of transmission of output coupler (T(OC)) on the laser performance has been investigated and found that the best laser performance was achieved with T(OC) = 50%. Average output power of 1 W was obtained with T(OC) = 50% at absorbed pump power of 5.4 W; corresponding optical-to-optical efficiency of 18.5% was obtained with respect to the absorbed pump power. Slope efficiency of 25% was measured with T(OC) = 50%. Laser pulses with pulse width of 26 ns, pulse energy of 37 mu J, and corresponding peak power of 1.4 kW with T(OC) = 50% were obtained. The lasers oscillate in multi-longitudinal-mode; number of the modes increases from two to five with pump power, owing to the mode selection by Cr,Yb:YAG thin plate acting as an intracavity etalon. (C) 2011 by Astro Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGa

Investigation of continuous-wave and Q-switched microchip laser characteristics of Yb:YAG ceramics and crystals

Continuous-wave and passively Q-switched microchip laser performance of Yb:YAG ceramics and single-crystals was investigated. Highly efficient continuous-wave Yb:YAG laser performance was observed at 1030 nm and 1049 nm for both Yb:YAG ceramics and crystals with different transmissions of output couplers. The laser performance of Yb:YAG ceramic is comparable to that of Yb:YAG single crystal. Meanwhile, the laser performance of laser-diode pumped Yb:YAG/Cr4+:YAG all-ceramics- and all-crystals-combination passively Q-switched microchip lasers were investigated. Sub-nanosecond laser pulses with peak power over 150 kW were obtained with different Yb:YAG/Cr4+:YAG combinations. Linearly polarized laser was observed in Yb:YAG/Cr4+:YAG all-crystals combination and circular polarized laser was obtained in Yb:YAG/Cr4+:YAG all-ceramics combination. The best laser performance was obtained with Yb:YAG/Cr4+:YAG all-crystals combination. (C) 2011 Elsevier B.V. All rights reserved