Zong Nan

Comparison of Nd:YAG Ceramic Laser Pumped at 885 nm and 808 nm

Laser performance of 1064 nm domestic Nd:YAG ceramic lasers for 885 nm direct pumping and 808 nm traditional pumping are compared. Higher slope efficiency of 34% and maximum output power of 16.5 W are obtained for the 885 nm pump with a 6 mm length 1 at.% Nd:YAG ceramic. The advantages for 885 nm direct pumping are discussed in detail. This pumping scheme for highly doping a Nd:YAG ceramic laser is considered as an available way to generate high power and good beam quality simultaneously.

High-Efficiency High-Power Nd: YAG Laser under 885 nm Laser Diode Pumping

A high-efficiency high-power Nd:YAG laser under 885nm laser diode (LD) pumping is demonstrated. The laser crystal is carefully designed, and the overlapping between the pump modes and the laser modes is optimized. The maximum output power at 1064 nm is 87W under the absorbed pump power 127.7W, corresponding to a slope efficiency of 72.4% and an optical-optical efficiency of 68.1%. The optical-optical efficiency is 58.4% for the pump power emitted directly from the LD. To our best knowledge, this is the maximal optical-optical conversion efficiency obtained for the LD end-pumped Nd:YAG lasers so far.

A Continuous-Wave Diode-Side-Pumped Tm:YAG Laser with Output 51 W

A compact diode-side-pumped Tm:YAG laser is presented, which can output 51 W of cw power at 2.02μm. The Tm:YAG rod is side pumped by nine diode arrays with the central wavelength of 783nm and the with bandwidth of about 2.5 nm at 25° C. To decrease the thermal effect on the both ends and dissipate the heat effectively, one composite Tm:YAG rod with the undoped YAG end caps and the screw threads on the side surface of the rod is used as the laser crystal. The maximum optical-to-optical conversion efficiency of the 2.02-μm laser output is 14.2%, with a slope efficiency of 26.8%.

High power high beam quality diode-pumped 1319-nm Nd:YAG oscillator-amplifier laser system

This paper demonstrated a high power and high beam quality diode-pumped 1319-nm Nd:YAG master oscillator-power amplifier laser system. A thermally near-unstable resonator with four-rod birefringence compensation flat-flat cavity was adopted as the master oscillator. A solid etalon was inserted in the unidirectional ring resonator to compress the laser linewidth. Under a repetition rate of 500 Hz and pulse width of 160 μs, the master oscillator delivers an average output power of 16.8 W at 1319 nm with linear polarisation, beam quality factor M2 = 1.16 and linewidth of 3.2 GHz. A double-pass power amplifier with two amplifier stages was employed for higher power scaling and the output power was amplified to be 25.9 W with M2 = 1.43.

Q-Switched Tm:YAG Laser Intracavity-Pumped by a 1064 nm Laser

We report a Q-switched 2-μm Tm:YAG laser based on intracavity-pumped by a 1064-nm Nd:YAG laser operating at room temperature for the first time. An average output power of 5.1 W is obtained with the repetition rate of 30 kHz and a pulse width of 300 ns. In addition, we demonstrate a 12.5-W continuous-wave 2-μm Tm:YAG laser, which is, to our best knowledge, the highest power for intracavity-pumping configuration.

Tunable and narrow linewidth yellow beam generation by sum-frequency mixing of diode-pumped Nd:YAG ring lasers

Output power of 1.1 W and linewidth of 0.7 GHz and beam quality of M2 = 1.2 yellow beam was generated by sum-frequency mixing 1064 nm and 1319 nm radiations of quasi-continuous-wave diode-pumped Nd:YAG lasers inside a pair of KTP crystals. The narrow linewidth 1064 nm and 1319 nm beams were realized by inserting solid etalons in the three-mirrors ring resonators. The wavelength of yellow laser was adjusted and controlled by the control of etalon angle and temperature. To achieve the high beam quality at the average power, thermally near-unstable resonators with two-rod birefringence compensation were designed and employed in the 1064 nm and 1319 nm ring lasers. The high sum-frequency efficiency was obtained by using a pair of KTP crystals with a walk-off-compensated configuration. The power of the diffraction-limited, narrow linewidth and precise-tunability yellow laser was reached to 1.1 W by mixing the 1064 nm beam of 7.5 W and the 1319 nm beam of 3.2 W.

Investigation on the scattering effect of ceramic Nd:YAG

This paper investigates the scattering effect of domestic 0.5 at % ceramic Nd:YAG. An effective method has been utilized to measure the scattering and absorption coefficients. An end-pumped continuous wave (CW) Nd:YAG ceramic laser was also demonstrated. A maximum output power of 6.7 W at 1064 nm was obtained at an 808-nm pump power of 32.9 W. Conversion efficiency and slope efficiency have been achieved. This indicates that scattering has an important effect on the optical performance of ceramic Nd:YAG.