Composite Crystal Laser Research Articles

Diode-Pumped Passively Mode-Locked YVO4/Nd:YVO4 Composite Crystal Laser

We report on a passively mode-locked YVO4/Nd:YVO4 composite crystal laser using a semiconductor saturable absorber mirror. At a pump power of 21.39 W, we achieve a 3.51 W average output power from a continuous wave mode-locked laser with a repetition rate of passively mode-locked pulse of 89 MHz and a pulse width of 38.3 ps. The pulse energy and peak power are 39.4 nJ and 1.03 kW, respectively. Our experiment results show that a composite crystal is an excellent laser crystal for mode locking.

CW and Q-switched GGG/Er:Pr:GGG/GGG composite crystal laser at 2.7 µm

We report the continuous-wave (CW) and passively Q-switched laser operations of a GGG/Er:Pr:GGG/GGG composite crystal at about 2.7 µm. Owing to the alleviation of the thermal lensing effect, the CW laser with a maximum output power of 463 mW was obtained with a slope efficiency of 15.5%. Based on the broadband saturable absorption property, a graphene saturable absorber (SA) mirror was fabricated and employed for realizing the Q-switched mid-infrared laser. Under an absorbed pump power of 2.47 W, an average output power of 186 mW was generated with a slope efficiency of 12.3%. The pulse width and the repetition rate of the laser were 360 ns and 120.5 kHz, respectively. These results indicate that the Er:Pr:GGG crystal, with the relatively lower upper-level lifetime, shows great promise for generating a short pulsed 2.7 µm mid-infrared laser using the graphene SA.

A compact, widely tunable intracavity PPLN optical parameter oscillator driven by an Nd:YAG/Cr:YAG composite crystal laser

Based on periodically poled lithium niobate (PPLN), a mini intracavity optical parameter oscillator (IOPO) driven by an diode-end-pumped composite Nd3+:YAG/Cr4+:YAG laser was demonstrated. The PPLN wafer has 20 domain reversal periods from 27.8 to 31.6 μm with a step of 0.2 μm between the neighbor periods. The output signal laser of OPO can be widely tunable in the range of 1402–1676 nm by changing the period at a certain temperature of 50°C. Under the diode pump power of 14 W, the maximum average output power of 600 mW at 1534 nm with pulse width of 2.0 ns and repetition rate of 16 kHz was obtained, corresponding to a peak power of 18.7 kW and a single pulse energy of 37.5 μJ, respectively.

Stationary generation of diode-pumped self-Raman Nd:YVO4/YVO4 composite crystal laser

Output power dependences of composite Nd 3+ :YVO 4 Raman laser stationary generation on the longitudinal diode pump power are measured at different transmissions of the output mirror at the Stokes radiation frequency. The deviation of the measured dependences from linear is explained by the influence of thermal effects on both the overlap of the beams and diffraction losses. A method to estimate the laser and Stokes losses in the cavity and the parameters characterizing the overlap of the laser radiation with the pump and Stokes beams is proposed. A Stokes-component of power 2.1 W is obtained and corresponds to 12% diode-to-Stokes efficiency.

A compact passively Q-switched intra-cavity frequency doubled Nd:YAG/Cr4+:YAG composite crystal green laser

A compact diode-end-pumped passively Q-switched intra-cavity frequency doubled Nd:YAG/Cr4+:YAG composite crystal laser was demonstrated. The pulsed laser at 532 nm was produced and the dependence of the average out power, pulse width and pulse repetition rate on incident pump power were measured. Under the pump power of 14 W, the minimum pulse width of 3.5 ns with repetition rate of 27.5 kHz was obtained, corresponding single-pulse energy of 18 μJ and peak power of 5.3 kW.

Control of pulse width in a diode-pumped doubly Q-switched composite crystal laser with AO and GaAs saturable absorber

The methods to control the pulse width of a laser-diode end-pumped doubly Q-switched Nd:YVO 4 /YVO 4 composite crystal laser with acoustic-optic (AO) and GaAs saturable absorber has been theoretically and experimentally studied. By varying the laser beam radius in the Q-switchers and the pump beam radius in the gain medium, we provide efficient means to control the pulse duration. The coupled rate equations are used to analyze the process of the laser. The experimental results are consistent with the theoretical results.

A diode side-pumped YAG/Nd:YAG/YAG composite crystal laser

A diode-bar side-pumped YAG/Nd:YAG/YAG composite crystal laser is presented. A maximum output power of 18.4 W at 1.064 μm with a slop efficiency of 57% and an optical-optical conversion efficiency of 46% was obtained for a pump power of 40 W. Compared with a side-pumped conventional crystal laser in the same experimental conditions, the side-pumped composite crystal laser improved the optical-to-optical conversion efficiency by 12%. Experimental results indicate that a composite crystal can depress the thermal effects effectively and improve the optical-to-optical conversion efficiency easily in the diode side-pumped lasers. The composite crystal has great potential in high-power diode side-pumped lasers.

Investigation of Nd:YVO 4/YVO 4 composite crystal and its laser performance pumped by a fiber coupled diode laser

Thermal effect control is critical to scale the output power of diode end-pumping solid lasers to several watts up and beyond. Diffusion bonding crystal has been demonstrated to be an effective method to relieve the thermal lens for the end-pumping laser crystal. The temperature distribution and thermal lens in Nd:YVO 4/YVO 4 composite crystal was numerically analyzed and compared with that of Nd:YVO4 crystal in this paper. The end-pumping Nd:YVO 4/YVO 4 composite crystal laser was set up and tested with z cavity. The maximum output power of 9.87 W at 1064 nm and 6.14 W at 532 nm were obtained at the pumping power of 16.5 W. The highest optical–optical conversion efficiencies were up to 60% at 1064 nm and 40% at 532 nm, respectively.