Browsing by Author "Huang, Tzu-Lin"

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Exploring the Emergence of the Self-Q-Switching in Diode-Pumped Yb:KGW Monolithic Lasers
(2018-09-01)
Huang, Tzu-Lin
;
Liang, Hsin-Chih
;
Su, Kuan-Wei
;
Chen, Yung-Fu
;
電子物理學系
We perform through experiments to explore the key factors for the emergence of a self-Q-switching phenomenon in diode-pumped Yb: KGW lasers. In addition to the output transmission, it is found that the mode-to-pump size ratio is a critical factor leading to the self-Q-switching. The region of the cavity mode volume without overlapping the pump volume plays a role of modulation loss to result in self-Q-switching. With an output transmission of 4% and a mode-to-pump size ratio of approximately 1.2, simultaneous self-Q-switching and self-mode-locking with the repetition rate of 23.1 GHz were experimentally observed. At an incident pump power of 9.2 W, the maximum pulse energy was estimated to be 1.4 mu J at the repetition rate of 880 kHz with an average output of 1.27 W.
Exploring the power scaling of the cryogenic 946 nm monolithic laser
(2018-08-01)
Cho, Chun-Yu
;
Huang, Tzu-Lin
;
Cheng, Hao-Ping
;
Huang, Kai-Feng
;
Chen, Yung-Fu
The criterion for achieving power scaling of the cryogenically cooled monolithic 946 nm laser is investigated by varying crystal length. Theoretical analysis of the mode-to-pump size matching indicates that the optimal power can be obtained with a crystal length of 8 mm. Furthermore, the pump-wavelength dependence of the output power can be less sensitive when a longer crystal was employed. We demonstrate 946 nm monolithic lasers with various crystal lengths to verify the theoretical analysis. The highest output power (30.2 W) is obtained by using an 8 mm Nd:YAG crystal at 130 K. Moreover, the output power reduction ratio is found to be smaller than 15% with the pump wavelength fluctuating between +/- 1 nm.
Flexibly Controlling the Power Ratio of Dual-Wavelength SESAM-Based Mode-Locked Lasers With Wedged-Bonded Nd: YVO4/Nd: GdVO4 Crystals
(2018-09-01)
Liang, Hsin-Chih
;
Huang, Tzu-Lin
;
Chang, Feng-Lan
;
Sung, Cheng-Lin
;
Chen, Yung-Fu
A new diffusion-bonded Nd: YVO4/Nd: GdVO4 hetero-structure crystal with oblique interface between two vanadate materials is exploited to achieve dual-wavelength passively mode-locked laser with a semiconductor saturable absorber mirror. Experimental results show that the power ratio of the two emission wavelengths can be flexibly adjusted by controlling the vertical position of pump beam. In the optimally balanced dual-wavelength operation, the maximum total output power of 2.5 W is obtained at an incident pump power of 11 Wand the pulse width is measured to be 24.7 ps with pulse repetition rate of 296.6 MHz. The mode-locked output pulse is further found to exhibit an optically beating with pulse duration of 1.8 ps at a repetition rate of 0.318 THz.
Orthogonally Polarized Self-Mode-Locked Lasers With Repetition Rate Multiplication up to Hundreds of Gigahertz: Observation of Temporal Carpets
(2018-09-01)
Chen, Yung-Fu
;
Chang, Ming-Ting
;
Huang, Tzu-Lin
;
Tung, Jung-Chen
;
Huang, Kai-Feng
Mode-locked laser sources with high repetition rates in the range of 10-1000 GHz are of considerable interest in modern communications, optical metrology, and photonic applications. Currently, developed laser systems generally suffer from the hardware complexity and energy loss. Here, we demonstrate a compact robust scheme based on a self-mode-locked monolithic Yb:KGW laser with external feedback coupling to achieve numerous repetition rate multiplications in the range of 25-330 GHz. The output pulse train consists of two orthogonally polarized components to form a vector state that is beneficial to practical applications. More intriguing, the pulse train measured as a function of the distance of the coupling feedback reveals a feature of the fractional recurrence that is like the Talbot carpet. An analytic formula is derived to manifest the formation of the temporal carpets. The developed experiment and formula not only pave a useful way for generating ultrahigh-repetition-rate femtosecond lasers but also provide new perspectives in the fractional recurrences of coherent waves.