Browsing by Author "Huang, T. L."

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Analysis of the optimal temperature for the cryogenic monolithic Nd:YAG laser at 946-nm
(2016-01-11)
Cho, C. Y.
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Huang, T. L.
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Cheng, H. P.
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Huang, K. F.
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Chen, Y. F.
The optimal temperature for the cryogenic monolithic Nd:YAG laser at 946-nm is theoretically and experimentally analyzed. It is clear that decreasing temperature can considerably eliminate the thermal population at the lower laser level to enhance the quantum efficiency. However, the narrowing of the absorption bandwidth for the gain medium leads to a reduction of the effective absorption efficiency as the temperature is decreased. Consequently, an optimal temperature for the maximum output power is found to be in the range of approximately 120 K to 140 K. It is experimentally verified that employing a pump source with a narrower emission spectrum linewidth contributes a more efficient output for the cryogenic laser. (C) 2016 Optical Society of America
Broad expansion of optical frequency combs by self-Raman scattering in coupled-cavity self-mode-locked monolithic lasers
(2017-04-03)
Chang, M. T.
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Huang, T. L.
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Liang, H. C.
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Su, K. W.
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Chen, Y. F.
Broad expansion of optical frequency comb (OFC) by the self-Raman scattering is numerically analyzed and experimentally accomplished in a coupled-cavity self-mode-locked (SML) monolithic Yb:KGW laser. The gain medium is coated to achieve the monolithic SML operation and a partially reflective mirror is further exploited to form the coupled cavity and to multiply the repetition rate up to 128.9 GHz. With a coupled reflectivity of 95%, it is experimentally found that not only the first-order but also second-order stimulated Raman scattering (SRS) can be efficiently generated. The mode-locked OFC can be consequently expanded to reach approximately 8.4 THz, leading the pulse width to be as narrow as 53 fs. At the pump power of 8.7 W, the total output power for the fundamental and the first-and second-Stokes waves can be maintained at 1.6 W. The present exploration provides a promising way to generate the ultrahigh-repetition-rate broadband OFC via the simultaneous SML and SRS processes. (C) 2017 Optical Society of America
Counter-intuitive Ge/Si/O interactions and Ge/Si symbiosis enable the creatation of new classes of exciting nanoelectronic and nanophotonic devices
(2017-01-01)
Hsueh, C. Y.
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Huang, T. L.
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Peng, K. P.
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Kuo, M. H.
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Lin, H. C.
We have successfully exploited multi-dimensional spaces of concentrations of the interstitial species, Si and Ge, geometries and compositions of the starting SiGe nano-pillar, and sources of Si interstitials (the Si3N4 and Si encapsulation layers) to create new classes of exciting optical and electronic devices such as single-electron tunneling devices, wavelength tunable photodetectors, and MOSFETs.
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.
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Sung, C. L.
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Huang, T. L.
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Wu, T. W.
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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.
Exploring the self-mode-locked dynamics of cryogenic diode-pumped Nd: YLF lasers: switching of orthogonal polarizations
(2017-08-01)
Huang, T. L.
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Cho, C. Y.
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Liang, H. C.
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Huang, K. F.
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Chen, Y. F.
The self-mode-locked output for cryogenic Nd:YLF laser at the temperature range of 90 K to 290 K is thoroughly investigated. Linearly polarized self-mode-locked lasing at 1047 nm (053 nm) with a repetition rate up to 1.59 GHz and a pulse width as short as 52 ps can be realized at temperatures above 155 K (below 135 K). Orthogonally polarized self-mode-locked operation can be observed at temperatures near 145 K. During dual-polarization operation, it is found that the polarized component with higher output power is the fundamental transverse mode, whereas the other component with lower output power becomes the high-order transverse mode. The dominant polarized component can be either pi- or sigma-polarization, depending on the fine adjustment of the cavity.
Generation and characterization of burst modes in passively mode-locked lasers with internal Fabry-Perot cavities
(2020-01-01)
Li, S. C.
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Huang, T. L.
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Hsieh, Y. H.
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Liang, H. C.
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Huang, K. F.
The generation of burst pulses in a multi-pass passively mode-locked laser is systematically explored. We exploit intracavity mirrors with different thicknesses to serve as reflected Fabry-Perot (RFP) cavities in laser resonators. Using a RFP cavity with the thinnest optical thickness, we can generate picosecond optical burst pulses with the highest intra-burst pulse rate of 33.12 GHz. The maximum output power of 2.6 W is obtained at an incident pump power of 11.9 W. We further develop an analytical model which considers the RFP effects to manifest the first-order autocorrelation and spectral behaviors in experiments. The agreement between theoretical analyses and experimental explorations provides the feasibility to flexibly manipulate the burst modes in practical applications. (C) 2019 Optical Society of America
Monolithic dual-polarization self-mode-locked Nd: YAG 946-nm lasers: controlling beat frequency and observation of temporal chaos
(2016-10-17)
Cheng, H. P.
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Huang, T. L.
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Lee, C. Y.
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Sung, C. L.
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Cho, C. Y.
The self-mode-locked (SML) operation at 946 nm can be achieved with a monolithic Nd: YAG crystal when the pump power is above the threshold of the multiple-longitudinal-mode generation. The SML output is further found to include two orthogonal polarization components with a beat frequency coming from the birefringence effect in the laser crystal. The beat frequency can be widely adjusted in the range of 5-220 MHz by controlling the cooling temperature. The present experiment also confirms the theoretical prediction that the two-mode operation generally exhibits the chaotic dynamics when the frequency difference is sufficiently close to the relaxation frequency. (C) 2016 Optical Society of America
Nd:YLF laser at cryogenic temperature with orthogonally polarized simultaneous emission at 1047 nm and 1053 nm
(2014-10-20)
Cho, C. Y.
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Huang, T. L.
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Wen, S. M.
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Huang, Y. J.
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Huang, K. F.
A Nd:YLF laser at cryogenic temperature is demonstrated for the first time with orthogonally polarized simultaneous emission at 1047 nm and 1053 nm. By exploring the temperature dependence of the fluorescence and the absorption spectra from the Nd: YLF crystal, the feasibility of simultaneous emission at low temperature is achieved. Due to the local heating from the pump absorption, the optimal temperature with respect to the pump power for balancing output powers of simultaneous emission is thoroughly explored. At the optimal temperature of 138 K, the total output power of the simultaneous emission can reach 3.1 W at an incident pump power of 7.9 W, corresponding to the optical to optical slope efficiency up to 43%. (C) 2014 Optical Society of America
Synchronized self-mode-locked 1061-nm and 1064-nm monolithic Nd:YAG laser at cryogenic temperatures with two orthogonally polarized emissions: generation of 670 GHz beating
(2016-09-19)
Huang, T. L.
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Sung, C. L.
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Cheng, H. P.
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Cho, C. Y.
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Liang, H. C.
A dual-wavelength self-mode-locked monolithic Nd: YAG laser at 1061 and 1064 nm is realized at cryogenic temperatures. At an incident pump power of 5.5 W, the total output power can reach 2.5 W and the mode-locked pulse width is 29 ps at a pulse repetition rate of 7.75 GHz. The synchronization of the dual-wavelength emissions leads to a beat frequency of 670 GHz in the individual mode-locked pulse. It is further discovered that the laser output consists of two orthogonally polarized components with a central frequency difference of 127 MHz. The central frequency difference between two orthogonal polarizations mainly arises from the external mechanical stress introduced by the copper holder for the laser crystal. (C) 2016 Optical Society of America
Very large photogain and high photorespone linearity of Ge-dot photoMOSFETs operating in accumulation-mode for monolithic Si photonics
(2017-01-01)
Kuo, Ming-Hao
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Liu, B. J.
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Huang, T. L.
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Lin, H. C.
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Li, Pei-Wen
We experimentally demonstrated that the inclusion of Ge dots into the gate stack of a Si MOSFET provides extremely high photoresponsivity over 1,000A/W and superior photoresponse linearity of at least 7 decades for 400-1300nm illumination, depending on whether the Ge-dot photoMOSFET operates in the inversion or accumulation modes. Remarkably a very large photocurrent gain of 10(3)-10(8)A/A and a significantly large dynamic range of photoresponse linearity with at least 6 decades for P-IN = 6nW-1.376mW are concurrently achievable for our Ge-dot photoMOSFETs in the accumulation-mode operation thanks to extremely low dark current of 40pA. Photocarrier generation and recombination under high power illumination is analytically simulated.