Browsing by Author "Wu, T. W."

Now showing 1 - 5 of 5

A high-power harmonically self- mode-locked Nd:YVO4 1.34-mu m laser with repetition rate up to 32.1 GHz
(2014-04-01)
Wu, T. W.
;
Tsou, C. H.
;
Tang, C. Y.
;
Liang, H. C.
;
Chen, Y. F.
We develop a practical method to achieve harmonically self-mode-locked operation in a Nd:YVO4 1.34-mu m laser for the generation of high-repetition-rate pulse trains. We exploit a gain medium with partial-reflection coating at the lasing wavelength to introduce effective mode selection. We numerically demonstrate that the coated gain medium can effectively modify the mode spacing of the laser cavity to be the harmonics of the free spectral range of the gain medium when the optical cavity length is adjusted to be commensurate with the optical length of the gain medium. We further employ a coated Nd: YVO4 crystal to realize harmonically mode-locked operation with a highest repetition rate of up to 32.1 GHz. At a pump power of 11.5 W, the average output power of 2.3 W is generated with a pulse duration as short as 5.7 ps. The locking range for the cavity length is also experimentally explored.
Dual-central-wavelength passively mode-locked diffusion-bonded Nd:YVO4/Nd:GdVO4 laser with a semiconductor saturable absorber mirror
(2017-08-01)
Chang, F. L.
;
Sung, C. L.
;
Huang, T. L.
;
Wu, T. W.
;
Cho, H. H.
A dual-central-wavelength passively mode-locked laser with full modulation in the 0.31 THz optical beating is achieved by using a diffusion-bonded Nd:YVO4/Nd:GdVO4 crystal and a semiconductor saturable absorber mirror. The output power of the dual-band emission is well balanced by tuning the focal position of the pump waist. At a pump power of 13 W, the total output power is up to 2.7 W with a repetition rate of 297.9 MHz. The autocorrelation traces clearly reveal the synchronization of the dual-band emission. Moreover, an analytical model is developed to manifest the multi-pulse structure caused by the etalon effect of the gain medium. More important, we experimentally verify that the etalon effect can be completely eliminated by using the wedge-cut diffusion-bonded Nd:YVO4/Nd:GdVO4 crystal.
Formation and recurrence of quasicrystalline patterns from quantum dynamics of suddenly released matter waves: Analogous manifestation of optical waves
(2012-07-01)
Liang, H. C.
;
Tung, J. C.
;
Wu, T. W.
;
Tsou, C. H.
;
Lin, Y. C.
We analytically and numerically verify that two-dimensional (2D) quasicrystalline matter waves can be formed from the free-time evolution of multiple Gaussian waves regularly distributed on a circular ring. We also demonstrate that an interesting recurrence phenomenon can be manifested by adding an extra Gaussian wave on the center of multiple Gaussian waves uniformly distributed on a ring. We finally employ an optical experiment for the coherent light passing through the mask to analogously illustrate the formation of 2D quasicrystalline patterns and the associated recurrence. Copyright (C) EPLA, 2012
Generation of pseudonondiffracting optical beams with superlattice structures
(2013-10-07)
Tsou, C. H.
;
Wu, T. W.
;
Tung, J. C.
;
Liang, H. C.
;
Tuan, P. H.
We demonstrate an approach to generate a class of pseudonondiffracting optical beams with the transverse shapes related to the superlattice structures. For constructing the superlattice waves, we consider a coherent superposition of two identical lattice waves with a specific relative angle in the azimuthal direction. We theoretically derive the general conditions of the relative angles for superlattice waves. In the experiment, a mask with multiple apertures which fulfill the conditions for superlattice structures is utilized to generate the pseudonondiffracting superlattice beams. With the analytical wave functions and experimental patterns, the pseudonondiffracting optical beams with a variety of structures can be generated systematically. (C) 2013 Optical Society of America
Total self-mode locking of multi-pass geometric modes in diode-pumped Nd:YVO4 lasers
(2013-10-01)
Liang, H. C.
;
Wu, T. W.
;
Tung, J. C.
;
Tsou, C. H.
;
Huang, K. F.
We report for the first time on simultaneously longitudinal and transverse self-mode locking in a diode-pumped Nd:YVO4 laser to achieve a pulse train traveling along the zigzag multi-pass trajectories in the degenerate cavity. At a pump power of 2.5 W, the average output powers in the mode-locked operation are 490 mW and 520 mW for the M-mode and Z-mode, respectively. The pulse widths are measured to be approximately 22.2 and 21.1 ps for the M-mode and Z-mode, respectively.