Chengfeng Yan

Efficient tunable diode-pumped Yb:LYSO laser

We demonstrated efficient laser action of a new ytterbium-doped oxyorthosilicate crystal Yb:LuYSiO(5) (Yb:LYSO) under high-power diode-pumping. The spectroscopic features and laser performance of the alloyed oxyorthosilicate crystal are compared with those of ytterbium-doped lutetium and yttrium oxyorthosilicates. In the continuous-wave laser operation of Yb:LYSO, a maximal slope efficiency of 96% and output power of 7.8 W were respectively achieved with different pump sources. The Yb:LYSO laser exhibits not only little sensitivity to the pump wavelength drift but also a broad tunability. By using a dispersive prism as the intracavity tuning element, we demonstrated that the continuous-wave Yb:LYSO laser exhibit a continuous tunability in the spectral range of 1014-1091 nm.

Growth and spectroscopic characteristics of Yb:GSO single crystal

For the first time, a high optical quality 10 at.% Yb3+-doped gadolinium oxyorthosilicate laser crystal Gd2SiO5 (GSO) was grown by the Czochralski (Cz) method. The segregation coefficient of Yb3+ was studied by the inductively coupled plasma atomic emission spectrometer (ICP-AES) method. The crystal structure has monoclinic symmetry with space group P 21/c; this was determined by means of an x-ray diffraction analysis. The absorption spectra, fluorescence spectra and fluorescence decay curves of Yb3+ ions in a GSO crystal at room temperature were also studied. Then, the spectroscopic parameters of Yb:GSO were calculated. The advantages of the Yb:GSO crystal include high crystal quality, quasi-four-level laser operating scheme, high absorption cross-sections and particularly broad emission bandwidth (~72 nm). The results indicated that the Yb:GSO crystal seemed to be a very promising laser gain medium in diode-pumped femtosecond laser and tunable solid state laser applications when LD pumped at 940 and 980 nm.

Efficient diode-pumped Yb:Gd2SiO5 laser

An efficient diode-pumped laser was demonstrated by using an ytterbium-doped laser crystal, Yb:Gd2SiO5 (Yb:GSO), wherein Yb3+ ions exhibit the largest ground-state splitting among all the ytterbium-doped crystals. The Yb:GSO laser can be operated at a low pumping threshold, and the most efficient laser occurs around 1088nm since the corresponding emission band has the largest emission cross section and the lowest thermal population. A slope efficiency of 75% was demonstrated for a continuous-wave Yb:GSO laser at 1094nm, and self-pulsed lasers were achieved within the tunable range of 1091–1105nm, which are the longest laser wavelengths achieved for Yb3+ lasers.

Diode-pumped continuous-wave and passively mode-locked Yb:GSO laser.

We report on both continuous-wave and passively mode-locked laser actions of a new ytterbium-doped laser crystal Yb:Gd(2)SiO(5) (Yb:GSO) under high-power diode-end-pumping. Due to the anisotropic and compact crystal structure, Yb:GSO exhibits a large manifold splitting of Yb(3+) ions, and a Yb:GSO laser can be operated efficiently with negligible reabsorption losses at emission wavelengths. In the continuous-wave operation, a Yb:GSO laser was operated with a slope efficiency of 49% near 1094 nm--the longest laser wavelength achieved for Yb(3+) lasers. Passive mode locking was obtained with a semiconductor saturable-absorber mirror. At a pump power of 6.23 W, a maximum average output power of 638 mW was obtained with the repetition rate of 145.5 MHz.

Tunable and efficient diode-pumped Yb3+:GYSO laser.

Result of diode-pumped cw laser action of Yb:GYSO are demonstrated for the first time. The laser wavelength could be tuned from 1030 to 1089 nm, and a slope efficiency of 57% was achieved.

Low-threshold and continuously tunable Yb:Gd2SiO5 laser

Yb:Gd2SiO5 (Yb:GSO) exhibits a large fundamental manifold splitting. Its long-wavelength emission band around 1088 nm, which has the largest emission cross section, encounters the lowest reabsorption losses caused by thermal population of the terminal laser level. As a result, low-threshold and tunable continuous-wave Yb:GSO lasers were demonstrated. A slope efficiency up to 86% and a pumping threshold as low as 127 mW were achieved for a continuous-wave Yb:GSO laser at 1092.5 nm under the pump of a high-brightness laser diode. A continuous tunability between 1000 and 1120 nm was realized with an SF14 prism as the intracavity tuning element. (c) 2006 American Institute of Physics.

Characterization of diode-pumped laser operation of a novel Yb:GSO Crystal

We report what is believed to be the first demonstration of the laser action of Yb/sup 3+/-doped Gd/sub 2/SiO/sub 5/ (Yb:GSO)crystal pumped by a 940-nm laser diode at room temperature. The threshold of laser generation is only 0.85 kW/cm/sup 2/, which is smaller than the theoretic threshold of Yb:YAG (1.54 kW/cm/sup 2/). The laser wavelength is 1090 nm. With a 2.5% output coupler, the maximum output power is 415 mW under a pump power of 5W. By using the SESAM, the Q-switched modelocking and CW mode-locked operations are demonstrated.

Continuous-wave diode-pumped Yb3+: LYSO tunable laser

A new alloyed crystal, Yb:LYSO, has been grown by the Czochralski method in our institute for the first time, and its effective diode-pumped cw tunable laser action was demonstrated. The alloyed crystal retains excellent laser properties of LSO with reduced growth cost, as well as the favorable growth properties of YSO. With a 5-at.% Yb:LYSO sample, we achieved 2.84 W output power at 1085 nm and a slope efficiency of 63.5%. And its laser wavelength could be tuned over a range broader than 80nm, from 1030nm to 1111 nm. This is the broadest tunable range achieved for Yb:LYSO laser, as far as we know.

Efficient operation of diode pumped tunable CW laser in Yb:Gd 2 SiO 5

A diode pumped cw laser operation based on 5-at.% doped Yb:GSO crystal was reported. The optical conversion efficiency of 64.5% at 1089 nm was achieved and the tuning range extends to ~65 nm.

Diode-Pumped Yb: Lu 2 SiO 5 lasers

Yb:LSO CW and Q-switched lasers pumped by diode lasers were demonstrated. Q-switched laser operated at 1058nm with InGaAs absorber. Pulse repetition was around 39KHz, slope efficiency of CW and Q-switched lasers were 22.2% and 3.0%.