Han Rao

Passively mode-locked Nd 3+ :YVO 4 laser using a molybdenum disulfide as saturable absorber

A molybdenum disulfide (MoS2) saturable absorber (SA) was fabricated by vacuum filtration method and employed to achieve passively mode-locked Nd3+:YVO4 laser. The optical properties of MoS2 were systematically characterized and the modulation depth was measured to be 7%. Stable continuous-wave mode-locked (CWML) laser at 1064.2 nm was realized with a pulse repetition frequency of 88.3 MHz and a pulse width of 12.7 ps. The maximum output power of 89 mW was obtained under an incident pump power of 2.1 W. The single pulse energy and peak power were calculated to be 1.0 nJ and 83.3 W, respectively.

A diode pumped passively mode-locked Nd:CaGdAlO4laser

A diode pumped passively mode-locked Nd:CaGdAlO4 (Nd:CGA) laser was demonstrated. By using a semiconductor saturable-absorber mirror (SESAM) as the modulator, stable mode-locked pulses with a duration of 6.0 ps and a repetition rate of 88.3 MHz have been achieved at a central wavelength of 1078.6 nm. The maximum output power of 452 mW was obtained under a pump power of 10 W.

Single frequency MOPA based on Nd:YAG single crystal fiber and rods

We demonstrate a single frequency 1064 nm master oscillator power amplifier (MOPA) system operating in macro-micro pulse scheme. The repetition rate for the macro pulses was 300 Hz with pulse duration of 300 μs. Micro pulses operated at 25 kHz. The master laser was a single-longitudinal-mode electro-optically Q-switched Nd:YAG laser with an output power of 250 mW and pulse duration of 33 ns. Three stages of power amplifiers based on Nd:YAG single crystal fiber and rods were designed. The final output power reached 31.3 W with pulse duration of 30 ns and linewidth of less than 130 MHz. Micro pulse energy of 13.9 mJ was obtained with a peak power of up to 464 kW. The beam quality factors (M2) were measured to be 1.56 and 1.76 in horizontal and vertical directions, respectively.

High power broadband LiF:F 2 - color center laser

A high power LiF:F(2)(-) color center laser is demonstrated with broadband emission. The excitation source is a quasi-continuous wave diode side-pumped acousto-optically Q-switched Nd:YAG laser. Under an incident 1064-nm laser power of 25.4 W, the highest output power of up to 4.7 W is obtained with a macro pulse repetition rate of 400 Hz and a micro pulse repetition rate of 50 kHz. The broadband emission is centered at 1142 nm with a bandwidth of 13 nm.

Single frequency MOPA based on Nd:YAG bulk and fiber single crystals

By employing Nd:YAG single crystal fiber and rods, single frequency 1064-nm master oscillator power amplifier is realized. Output power is 31.3 W with peak power of 464 kW and linewidth of less than 130 MHz.

Actively Q-switched Nd:YAG twisted-mode cavity laser with a RTP electro-optic modulator

A single-longitudinal-mode Nd:YAG laser was demonstrated using a twisted-mode cavity and an etalon. Stable laser pulses at 10 kHz were obtained with a RTP electro-optic modulator. Under an incident pump power of 8.1 W, the maximum output power of the single-longitudinal-mode laser was 1.07 W, and the linewidth was less than 0.1 GHz.

Single-frequency Nd:GGG/BaWO 4 Raman laser emitting at 1178.3 nm

An actively Q-switched Nd:GGG/BaWO<inf>4</inf> single-frequency Raman laser at 1178.3 nm is demonstrated. Under a pulse repetition rate of 20 kHz, the maximum pulse energy was 12 μJ and the linewidth was less than 4.34×10⁻³ cm⁻¹.

High-repetition-rate widely tunable LiF : color center lasers

High-repetition-rate tunable LiF: color center lasers pumped by quasi-continuous-wave diode-side-pumped acousto-optically Q-switched Nd:YAG laser are demonstrated. Littrow-grating and Littman-grating tuning schemes are studied respectively. In the Littrow-grating scheme, the tuning range was 1085 nm to 1275 nm, and the maximal average output power was 275 mW. In the Littman-grating scheme, the tuning range was 1105.5 nm to 1215.5 nm, and the maximal average output power was 135 mW.