Tieli Zhang

8.3 W diode-end-pumped continuous-wave Nd:YAG laser operating at 946-nm

This paper reports a diode-end-pumped continuous-wave (CW) Nd:YAG laser operating at 946-nm by utilizing the 4F3/2-4I9/2 transition. We demonstrated that at an incident pump power of 27.7 W, an output power of 8.3-W could be achieved with a slope efficiency of 33.5%. To the best of our knowledge, this is the highest CW output power at 946 nm generated by LD end-pumped Nd:YAG lasers. By using intracavity frequency doubling with an LBO crystal, we further obtained a 473-nm blue laser with an output power of 1.2 W, achieving an optical-to-optical conversion efficiency of 7.1% at a pump power of 16.9 W. The short-term power instability of the blue laser was less than 1 %.

Experimental study on a high conversion efficiency, low threshold, high-repetition-rate periodically poled lithium niobate optical parametric generator

A high-conversion-efficiency, low-threshold, quasi-continuous-wave optical parametric generator (OPG) based on a periodically poled lithium niobate (PPLN) crystal is presented. Pumped by an acousto-optically Q-switched 1064 nm Nd:YAG laser with a power output of 848 mW, the OPG generated an output power of 452 mW for the signal and the idle waves, achieving an internal conversion efficiency of 62.7% and a slope efficiency of 75.6%. To the best of our knowledge, this is the highest efficiency ever reported for single-pass, quasi-continuous-wave OPGs by using periodically poled crystals.

Tunable dual-signal PPLN optical parametric generator by using an acousto-optic beam splitter

A tunable dual-signal optical parametric generator (OPG) based on multi-grating periodically poled lithium niobate (PPLN) is presented. An acousto-optic device (AOD) was used as a beam splitter outside the cavity of a high-repetition-rate, Q-switched 1064 nm Nd:YAG laser. A synchronous and widely tunable dual-signal OPG was obtained by coupling the split beams into two parts with different poled periods in the same PPLN crystal and by tuning the temperature of the crystal. A total conversion efficiency of 27.9% was achieved when the system operated at 1687 and 1864 nm.

High-repetition-rate dual-signal intracavity optical parametric generator based on periodically-phase-reversal PPMgLN

A high-repetition-rate dual-signal intracavity optical parametric generator (IOPG) inside a diode-end-pumped acousto-optically (AO) Q-switched Nd:YVO4 laser is presented. The nonlinear material is a periodically-phase-reversal periodically poled MgO-doped lithium niobate (ppr-PPMgLN). At an incident diode pump power of 6.1?W and a Q-switch repetition rate of 20?kHz, an average dual-signal output power of 0.44?W is achieved. The dual-signal wavelengths of 1477 and 1491?nm are obtained at a crystal temperature of 40??C. The measurements of the beam quality factor of 1.4 and the pulse duration of 77?ns show good spatial and temporal overlaps for the dual-signal radiation.

High conversion efficiency continuous wave quasi-phase-matched second harmonic generation in MgO doped stoichiometric lithium tantalate

In this paper, for the first time we have demonstrated a continuous wave single-pass extracavity frequency doubling by use of MgO doped stoichiometric lithium tantalite (PP-MgO: SLT). The maximum output of the second harmonic green light is 905mW with the pumping power of 7.69W. The second harmonic conversion efficiency is 11.77%. We have theoretically calculated the tolerance of the temperature of SLT SHG which is about 1.5°C. The experimental tolerance of the temperature is consistent with the calculated value.

Theoretical Investigation of Dual-wavelength Terahertz Wave Generation Based on Slant-Stripe-Type Periodic Poled Lithium Niobate Crystal

We propose a method for generating dual-wavelength terahertz radiation with a surface emitted configuration based on slant-stripe-type periodic poled lithium niobate (PPLN) crystal. The crystal is designed to be phase reserved for two difference frequency generation processes so that the predesigned dual-wavelength terahertz radiation at 1.43 THz and 2.07 THz can be achieved simultaneously. The estimated effective nonlinear coefficient as a function of the terahertz radiation frequencies is also included in our discussion. Theoretical analysis shows that the central frequency of the predesigned terahertz radiation will shift inconspicuously due to the permitted fabrication inaccuracy of the crystal period.

Theoretical Analysis of Broadband Source by Using Retracing Behavior of Collinear Quasi-Phase-Matching Optical Parametric Generator

According to the concept of phase matching bandwidth the band width of broadband source by using retracing behavior of collinear quasi-phase-matching (CQPM) optical parametric generator (OPG) in periodically poled lithium niobate (PPLN) is presented firstly. Comparing the various pump wavelengths we obtain the pumping condition and parameters of PPLN to realize the broadband source near 1550 nm in the CQPM-OPG. In theory we present the optimum pump wavelength and the maximum ideal bandwidth range to be 940.75 nm and 1475~1681 nm respectively.

Dual-signal-wavelength Optical Parametric Generator Based on ppr-PP-MgO:LN

A pulsed nanosecond optical parametric generator(OPG) in a periodically phased-reversed MgO-doped periodically poled lithium niobate(ppr-PP-MgO:LN) was demonstrated. Two pairs of signal waves and idler waves were obtained with a maximum output power of 135 mW repeating at a rate of 25 kHz.