Weixia Lan

Theoretical and experimental studies on output characteristics of an intracavity KTA OPO

An acousto-optically Q-switched Nd:YVO(4)/KTiOAsO(4) (KTA) intracavity optical parametric oscillator (OPO) is efficiently realized in singly resonated scheme. With an end-pumping diode power of 25.9 W, output signal (1535 nm) power of 3.77 W and idler power (3467 nm) of 1.18 W are obtained at a pulse repetition rate of 50 kHz. A rate-equation model is set up to simulate the output power and time characteristics of both signal and idler waves. And both the numerical and experimental results show that the idler pulse width is shorter than the signal one in a singly resonant OPO.

Simultaneous dual-wavelength operation of Nd:YVO 4 self-Raman laser at 1524 nm and undoped GdVO 4 Raman laser at 1522 nm

A diode-pumped, actively Q-switched dual-wavelength laser employing Nd:YVO(4) self-Raman emission at 1524 nm and undoped GdVO(4) Raman emission at 1522 nm is demonstrated. With a pump power of 21.5 W and pulse repetition frequency of 20 kHz, a maximum dual-wavelength output power of 1.62 W was obtained, comprising a 0.54 W, 1522 nm Raman component and 1.08 W, 1524 nm self-Raman component. The corresponding dual-wavelength Raman pulse width was 5.6 ns. The experimental results indicate that this laser, with quite small wavelength separation, was effective by virtue of simultaneous self-Raman and Raman shifts.

1st-Stokes and 2nd-Stokes dual-wavelength operation and mode-locking modulation in diode-side-pumped Nd:YAG/BaWO 4 Raman laser

1st-Stokes and 2nd-Stokes dual-wavelength operation within a diode-side-pumped Q-switched Nd:YAG/BaWO(4) intracavity Raman laser was realized. Using an output coupler of transmission of 3.9% at 1180 nm and transmission of 60.08% at 1325 nm, the maximum output power of 8.30 W and 2.84 W at a pulse repetition rate of 15 kHz for the 1st Stokes and the 2nd Stokes laser were obtained, respectively. The corresponding optical conversion efficiency from diode laser to the 1st Stokes and 2nd Stokes laser are 5.0% and 1.4%, respectively. With the pump power of 209 W and a pulse repetition rate of 15 kHz, the 1st Stokes and the 2nd Stokes pulse widths were 20.5 ns and 5.8 ns, respectively. The stable simultaneous Q-switching and mode locking of the 2nd Stokes laser without mode locking component was obtained at the pump power of about 29~82 W. The estimated mode-locked pulse width was approximately 31 ps at the pump power of 50 W and a pulse repetition rate of 15 kHz.

Second-Stokes dual-wavelength operation at 1321 and 1325 nm ceramic Nd:YAG/BaWO 4 Raman laser

A diode-pumped, actively Q-switched second-Stokes dual-wavelength laser employing ceramic Nd:YAG as the gain medium and BaWO(4) as the Raman medium is demonstrated. The dual-wavelength Raman laser emission at 1321 and 1325 nm is based on the dual-wavelength fundamental laser emission at 1061 and 1064 nm. With a pump power of 18.4 W and pulse repetition frequency of 15 kHz, a maximum dual-wavelength output power of 1.67 W was obtained, comprising a 0.75 W, 1321 nm laser component and a 0.92 W, 1325 nm laser component. The corresponding dual-wavelength second-Stokes pulse width was 2.9 ns.

Simultaneous Dual-Wavelength Generation at 1502 and 1527 nm in Ceramic Neodymium-Doped Yttrium Aluminum Garnet/BaWO4 Raman Laser

A diode-pumped, actively Q-switched eye-safe dual-wavelength laser employing ceramic neodymium-doped yttrium aluminum garnet (Nd:YAG) as gain medium and BaWO4 as Raman medium is demonstrated for the first time to the best of our knowledge. The dual-wavelength Raman laser emission at 1502 and 1527 nm is based on the dual-wavelength fundamental laser emission at 1319 and 1338 nm. With a pump power of 17.3 W and pulse repetition frequency of 20 kHz, a maximum dual-wavelength output power of 0.82 W was obtained, comprising a 0.37 W, 1505 nm laser component and a 0.45 W, 1527 nm laser component.

A frequency-doubled Nd:YAG/KTP laser at 561 nm with diode side-pumping

An intracavity KTiOPO4 (KTP) frequency doubling laser emitting at 561?nm is achieved within a diode side-pumped acousto-optically Q-switched Nd:YAG laser. A compact convex?flat straight cavity is employed to achieve the compact configuration, where coatings are specially designed to suppress unwanted lines. At the pump power of 147?W and the pulse repetition rate of 10?kHz, the output power of 8.1 W was obtained at 561?nm. The corresponding optical-to-optical conversion efficiency is 5.5%. The pulse width of a 561?nm wave is 210?ns. The M2 factors are measured to be 15.5 and 17.5 in the horizontal and vertical directions respectively.

Passively Q-Switched Intracavity BaTeMo2O9 Raman Laser

A diode-end-pumped passively Q-switched intracavity Raman laser at 1179 nm is obtained with the BaTeMo2O9 nonlinear Raman crystal for the first time. With an incident pump power of 12.3 W, the average output power of 1179 nm is obtained to be 0.41 W. The pulse repetition rate is measured to be 24 kHz and the pulse width is 5.2 ns. The beam quality factors (M2) in the horizontal and vertical directions are determined to be 1.5±0.1 and 2.0±0.1, respectively.

Intracavity KTiOAsO4 optical parametric oscillator pumped by an actively Q-switched Nd:YAG laser

A KTiOAsO4 (KTA) intracavity optical parametric oscillator (IOPO) is achieved within a diode end-pumped acousto-optically Q-switched Nd:YAG laser. With a 25-mm-long X-cut KTA crystal, efficient parametric conversions to signal (1535 nm) and idler (3467 nm) waves are realized. At an incident diode power of 14.9 W, the highest output power of 1.83 W including 1.37 W of signal and 0.46 W of idler radiations are obtained at a repetition rate of 40 kHz, corresponding to a total optical-to-optical conversion efficiency of 12.3%. Rate equations model are used to simulate this system, and the theoretical results agree with the experimental ones.

Theoretical and Experimental Study on the Intracavity Optical Parametric Oscillator Pumped in a Raman Laser

A rate-equation-based model is established to describe the behavior of an intracavity optical parametric oscillator (OPO) pumped in an actively -switched Raman laser system. The intracavity photon densities and the initial population inversion density are assumed to be Gaussian distribution. These coupled rate equations are solved numerically. In the experiment, a laser diode end-pumped acousto-optically -switched KTP-OPO pumped by a Nd:YAG/ Raman laser is demonstrated. The output characteristics are studied carefully. And the experimental results about the average output power agree with the numerical solutions.

Theoretical and experimental studies on passively Q-switched KTiOAsO4 optical parametric oscillator

A passively Q-switched intracavity optical parametric oscillator based on KTiOAsO4 (KTA) crystal is studied theoretically and experimentally. The rate-equation-based theoretical model is established to describe the time evolutions of the population inversion density of the laser crystal, ground-state population density of the saturable absorber, fundamental photon density, signal photon density and the idler photon density. In the experiment, a laser diode-end pumped, passively Q-switched Nd:YAG/KTA IOPO with a Cr4+:YAG crystal as the saturable absorber is realized to verify this model. The characteristics including the output power, the pulse repetition rate, the pulse width and the beam quality were investigated for this OPO. The experimental results for the output power and the repetition rate agree with the theory well. And both results show that with same pumping level the idler pulse width is shorter than the signal one.