Shutao Dai

Efficient 2122 nm Ho:YAG laser intra-cavity pumped by a narrowband-diode-pumped Tm:YAG laser

We first demonstrate an efficient Ho:YAG laser intra-cavity pumped by a narrowband-diode-pumped Tm:YAG laser. The pump wavelength of the laser diode was selected according to the excitation peak which is also one of the absorption peaks of a 3.5 at. % Tm:YAG crystal and was locked by volume Bragg gratings. In the Tm laser experiment, a maximum output power of 11.12 W, corresponding to a slope efficiency of 51.6%, was obtained. In the Ho laser experiment, a maximum output power of 8.03 W at 2122 nm with a slope efficiency of 38% was obtained for 24.96 W of diode pump power incident on the Tm:YAG rod.

0.95 W high-repetition-rate, picosecond 335 nm laser based on a frequency quadrupled, diode-pumped Nd:YVO(4) MOPA system.

An efficient all-solid-state picosecond (ps) ultraviolet (UV) laser at 335 nm was demonstrated based on frequency quadrupling of a mode-locked 1342 nm MOPA system. An output power of 0.95 W was obtained under a fundamental wave power of 16.38 W, corresponding to a conversion efficiency of 5.8% from infrared to UV. The repetition rate and pulse duration were 77 MHz and 20.2 ps, respectively. The beam quality factor M(2) was measured to be 1.56. This is, to the best of our knowledge, the highest output power at 335 nm.

Design and performance of a composite Tm:YAG laser pumped by VBG-stabilized narrow-band laser diode

A 2-μm composite Tm:YAG laser pumped with a narrow-band laser diode was presented. The temperature distribution and thermal lens in the Tm:YAG were numerically simulated by a finite element method and the results were used to design the special cavity, in order to achieve a high efficiency and stable output. With a 25-W incident pump power, we obtained a maximum output power of 11 W at 2018.5 nm, corresponding to a slope efficiency of 51.3% and an optical-to-optical efficiency of 44.5%, respectively. The beam quality was measured to be and .

Generation of 3.8-GHz Picosecond Pulses From a Diode-Pumped Self-Mode-Locked Yb:YAG Thin Disk Laser

We report on a high-repetition-rate self-mode-locking laser with a diode-pumped Yb:YAG ceramic thin disk. The third nonlinearity of the gain medium is exploited to achieve stable CW mode-locking operation without using any additional components in the cavity. The laser produces 60-ps pulses at the central wavelength of 1032 nm with a repetition rate of 3.8 GHz and an average power of 780 mW.

Development of an injection-seeded single-frequency laser by using the phase modulated technique

An injection-seeded single-frequency Q-switched Nd:YAG laser is accomplished by using a phase modulated ramp-fire technique. A RbTiOPO4 (RTP) electro-optic crystal is selected for effective optical path length modulation of the slave self-filtering unstable resonator. This single-frequency laser is capable of producing 50 mJ pulse energy at 1 Hz repetition rate with a pulse width of 16 ns. The standard deviation of laser pulse intensity for consecutive 100 shots from the mean pulse intensity is less than 1.05%. A spectral linewidth of less than 0.5 pm with a frequency jitter of about 14 fm over 30 min is obtained.

High-repetition-rate single-frequency electro-optic Q-switched Nd:YAG laser with feedback controlled prelase

A stable high-repetition-rate, high pulse energy and single-frequency electro-optic Q-switched laser has been developed and demonstrated in this paper. The prelase technique has been used in this single-frequency laser. And a PID feedback control electronics is applied to stabilize the prelase. Meanwhile, a two-plate resonant reflector take the place of traditional dielectric output coupler mirror to enhance the single-axial-mode selection. And a Cr:YAG saturable absorber is also inserted in the cavity to improve single-axial-mode selection. Output laser power over 2 W with 10 ns pulse duration has been obtained at a repetition rate of 1 kHz. And the single-axial-mode probability was 100% in one hour without any manual adjustments. The experimental results show that the prelase technique is reliable to attain single-frequency operation.