Du Shifeng

Green Output of 1.5 W from a Diode-Pumped Intracavity Frequency-Doubled Self-Q-Switched and Mode-Locked Cr,Nd:YAG Laser

The spontaneous emmission (SE) progress of polarized atoms in a stratified structure of air-dielectric (D0-metal(M)-dielectric(D1)-air can be controlled effectively by changing the thickness of the D1 layer and rotating the polarized direction of atoms. It is found that the normalized SE rate of atoms located inside the D0 layer crucially depends on the atomic position and the thickness of the D1 layer. When the atom is located near the D0-M interface, the normalized atomic SE rate as a function of the atomic position is abruptly onset for the thin D1 layer. However, with the increasing thickness of the D1 layer, the corresponding curve profile exhibits plateau and stays nearly unchanged. The substantial change of the SE rate stems from the excitation of the surface plasmon polaritons in metal-dielectric, and the feature crucially depends on the thickness of D1 layer. If atoms are positioned near the D0-air interface, the substatial variation of the normalized SE rate appears when rotating the polarized direction of atoms. These findings manifest that the atomic SE processes can be flexibly controlled by altering the thickness of the dielectric layer D1 or rotating the orientation of the polarization of atoms.

Observation of Antiphase State in a Self-Q-switched Nd, Cr:YAG Laser

We experimentally investigate the antiphase dynamics phenomenon in a self-Q-switched Nd, Cr:YAG laser operating at 946 nm. Due to the effect of spatial hole burning, the Q-switched pulses sequences of one, two and three modes at different pump power are observed. The experimental results show that the pulse sequences display classic antiphase dynamics.

Spectroscopic investigation of a new crystal: Nd3+,Yb3+:YVO4

The absorption and emission spectra of the YVO4 single crystal co-doped with 1 at.% Nd3+ and 1 at.% Yb3+ are investigated. The efficient Nd3+ → Yb3+ energy transfer and the back transfer (Yb3+ → Nd3+) are observed at room temperature. The fluorescence lifetime of the 4F3/2 level of Nd3+ in Nd, Yb:YVO4 is measured under 808 nm laser light excitation. The efficiency of Nd3+ → Yb3+ energy transfer in YVO4 is determined to be about 34%.

A Compact High Power Laser-Diode Side-Pumped Tm,Ho:YAG Laser Nearly at Room Temperature with Intracavity Tm:YAG Laser

We report a compact high power Tm,Ho:YAG laser nearly at room temperature. The laser-diode side-pumped Tm:YAG and Tm,Ho:YAG laser modules are operated in the same cavity. The laser yields 37.34 W of continuous wave output power under the temperature of 6°C, corresponding to a maximum slope efficiency of 16.7% when the output power lies from 5.1 W to 27.0 W. This is the first report on the combined Tm:YAG and Tm,Ho:YAG lasers for obtaining high power 2.1 μm laser.

Diode end-pumped self-Q-switched and mode-locked Nd,Cr:YAG /KTP green laser

We first experimentally demonstrate a laser-diode end-pumped self-Q-switched and mode-locked Nd,Cr:YAG green laser with a KTP crystal as the intra-cavity frequency doubler. The device produces an average output power of 680 mW at 532 nm. The corresponding pulse width of the Q-switched envelope of the green laser is 170 ± 20 ns. The mode-locked pulses have a repetition rate of approximately 183 MHz and the average pulse duration is estimated to be around sub-nanosecond. It is found that the intra-cavity frequency doubling greatly improves the modulation depth and stability of the mode-locked pulses within the Q-switched envelope.