Shifeng Du

High Efficiency and High Peak Power Picosecond Mid-Infrared Optical Parametric Amplifier Based on a New Crystal BaGa 4 Se 7

A high efficiency and high peak power picosecond (ps) mid-infrared optical parametric amplifier with a new nonlinear crystal BaGa(4)Se(7) pumped by a 30 ps 1064 nm Nd:YAG laser is demonstrated for the first time. The maximum photon conversion efficiency of 56% from 1064 nm to 3.9 μm idler has been achieved at the pump energy of ~1.8 mJ. A maximum idler output of 830 μJ at 3.9 μm with peak power of ~27 MW was obtained at pump energy of ~9.1 mJ. Moreover, a 3-5 μm idler tuning range was demonstrated, with output energies of ~300 μJ at 5 μm and up to 1 mJ at 3 μm at ~8.2 mJ pump energy.

Wavelength Switchable High-Power Diode-Side-Pumped Rod Tm: YAG Laser around 2µm

We report a high-power diode-side-pumped rod Tm:YAG laser operated at either 2.07 or 2.02 µm depending on the transmission of pumped output coupler. The laser yields 115W of continuous-wave output power at 2.07 µm with 5% output coupling, which is the highest output power for all solid-state 2.07 μm cw rod Tm:YAG laser reported so far. With an output coupler of 10% transmission, the center wavelength of the laser is switched to 2.02 μm with an output power of 77.1 W. This is the first observation of high-power wavelength switchable diode-side-pumped rod Tm:YAG laser around 2 µm.

A 171.4 W Diode-Side-Pumped Q-Switched 2 μm Tm:YAG Laser with a 10 kHz Repetition Rate

A 785 nm diode-side-pumped high-power high-pulse-repetition-frequency Q-switched 2μm Tm:YAG laser system is reported. Under a pump power of 1300 W, a 171.4 W average output power is achieved at a pulse repetition frequency of 10 kHz. To our knowledge, this is the highest average output power for a diode-pumped all solid-state Q-switched 2 μm Tm:YAG laser. The laser output corresponds to an optical-to-optical conversion efficiency of 13.3% and a slope efficiency of 18.9%.

High-power diode-side-pumped rod Tm:YAG laser at 2.07 μm

We report a high-power diode-laser (LD) side-pumped rod Tm:YAG laser of around 2 μm. The laser was water-cooled at 8°C and yielded a maximum output power of 267 W at 2.07 μm, which is the highest output power for an all solid-state cw 2.07 μm rod Tm:YAG laser reported as far as we know. The corresponding optical-optical conversion efficiency was 20.7%, and the slope efficiency was about 29.8%, respectively.

Tomographic Imaging and Three-Dimensional Reconstruction Based on a High-Gain Optical Parametric Amplifier

Tomographic imaging and three-dimensional reconstruction based on a high-gain picosecond optical parametric amplifier (OPA) is demonstrated. More than 40 dB intensity amplification of the image is achieved from the high-gain OPA. The images of various longitudinal positions of the target are extracted by the gated nature of the OPA, then a three-dimensional (3-D) surface topography of the target is reconstructed. The gated and high-gain property of the OPA allows tomographic optical imaging together with 3-D profile reconstruction of the target in turbid media.