J. Kong

9.2‐W diode–end–pumped Yb:Y2O3 ceramic laser

We report on a high-power diode–end–pumped polycrystalline Yb:Y2O3 ceramic laser. Under the pump power of 27W, continuous-wave output power of 9.2W at 1078nm has been obtained by using an output coupler of R=96%. The laser had a threshold of 3.1W and a slope efficiency of 41%. Comparative studies on the laser performance between the Yb:Y2O3 ceramic and the Yb:yttrium aluminum garnet (YAG) single crystal show that at the same doping concentration of 8at.%, higher laser efficiency can be obtained in the Yb:Y2O3 ceramic laser than in the Yb:YAG single crystal laser.

Diode-pumped Yb:Y2O3 ceramic laser

We report on a diode-pumped polycrystalline Yb:Y2O3 ceramic laser. We demonstrate that, with a pump power of 11 W at 937 nm, 0.75-W cw laser output at 1078 nm can be obtained from the laser. The laser had a threshold of 4.7 W and a slope efficiency of 12.6% when an output coupler of R=98% was used.

High-efficiency 1040 and 1078 nm laser emission of a Yb:Y2O3 ceramic laser with 976 nm diode pumping.

We report a high-efficiency diode-end-pumped polycrystalline Yb:Y2O3 ceramic laser. Pumped by a 976 nm laser diode bar and with an absorbed pump power of 2.8 W, cw output power of 1.74 W at 1078 nm, and 0.73 W at 1040 nm were obtained. The slope efficiency was measured to be 82.4% for the 1078 nm laser emission and 57.1% for the 1040 nm laser emission.

Diode-end-pumped 4.2-W continuous-wave Yb:Y2O3 ceramic laser.

We report on an efficient diode-end-pumped polycrystalline Yb:Y2O3 ceramic laser. Continuous-wave output power of 4.2 W at 1078 nm was obtained under pump power of 19.5 W. The corresponding slope efficiency was 29%. The beam quality factor (M2) at full pump power was measured to be 1.63. The threshold wavelengths of the laser at various output couplings were also investigated. It was found that the threshold wavelengths shifted approximately 5 nm when the reflectivity of the output coupler changed from 90% to 99.9%, as caused by the strong reabsorption effect in the ceramic sample.

Passively Q-switched Yb:Y 2 O 3 ceramic laser with a GaAs output coupler

We report on the experimental studies of a diode-end-pumped passively Q-switched Yb:Y(2)O(3) ceramic laser with a GaAs wafer simultaneously as saturable absorber and output coupler. The Q-switched operation of the laser has an average output power of 0.51 W with a 17.7-W incident pump power. The Q-switched pulses with pulse energy of 7.7 microJ have been achieved. The minimum pulse width is measured to be about 50 ns with a repetition rate of 52.6 KHz. To our knowledge, this is the first demonstration on a passively Q-switched Yb:Y(2)O(3) ceramic laser.

Random-wavelength solid-state laser

The spectral properties of a diode-pumped Yb:Y2O3 ceramic laser are reported. We show experimentally that the instantaneous emission wavelengths of the laser change randomly with time, whereas its emission has fixed well-defined transverse modes. The central wavelength of the laser emission also shifts prominently with the increase of intracavity light intensity. It is found that the spectral properties of the laser can be explained well based on the strong reabsorption of light in the gain medium.

Diode end-pumped passively Q-switched Nd:YAG ceramic laser with Cr4+:YAG saturable absorber

We report on a diode end-pumped passively Q-switched Nd:YAG ceramic laser. By using a Cr4+:YAG single crystal with an 80% initial transmission as the saturable absorber, stable Q-switched pulses with a 126-μJ pulse energy, a 12-ns pulse width, and an 8.4-kHz pulse repetition rate have been obtained. The Q-switching performance of the laser under different saturable absorption strengths and output couplings was experimentally investigated.

Temperature-tuning optical parametric oscillator based on periodically poled MgO:LiNbO 3

We report experimental results on an efficient singly resonant optical parametric oscillator (OPO) based on periodically poled MgO-doped LiNbO 3 . The OPO was pumped by a diode-pumped passively Q-switched Nd:GdVO 4 laser, which could produce 3-ns laser pulses with a repetition rate of 5 kHz. By changing the crystal temperature and grating periods, the OPO generated signal and idler output in the ranges of 1.41 to 1.78 μm and 2.7 to 4.3 μm, respectively. The maximum output power at the signal wavelength of 1.55 μm was 35.4 mW with 120-mW pump power. The possibility of using the OPO for trace gas detection was demonstrated through measuring the absorption spectra of methane.

Diode-end-pumped passively Q-switched Nd:YAG ceramic laser

We report on a diode-end-pumped passively Q-switched Nd:YAG ceramic laser. By using a Cr4+:YAG single crystal of 80% initial transmission as the saturable absorber, stable Q-switched pulses with 126 mu J pulse energy, 12 ns pulse width and 8.4 kHz pulse repetition rate have been obtained.

Trace-gas detection based on the temperature-tuning periodically poled MgO: LiNbO3 optical parametric oscillator

We report on the use of the temperature-tuned optical parametric oscillator for trace gas detection. A synchronization trace gas detection system was designed and demonstrated, in which the measuring errors caused by the instability of the OPO could be greatly reduced. The trace gas detection system was based on a periodically poled MgO-doped LiNbO3 optical parametric oscillator (OPO) which was pumped by a diode-pumped passively Q-switched Nd:GdVO4 laser. The OPO could produce wavelength-tunable signal output through changing the crystal temperature and the grating periods. The usefulness of the trace gas detection system for spectroscopy was demonstrated by directly measuring the photon absorption spectrum of the methane and acetylene gas cells.