Browsing by Author "Lai, H. C."

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Electron transport and electroluminescent efficiency of conjugated polymers
(2009-01-01)
Tseng, S. R.
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Chen, Y. S.
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Meng, H. F.
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Lai, H. C.
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Yeh, C. H.
The relation between charge balance and electroluminescent efficiency for polymers is studied systematically in this work. Light-emitting diodes of several kinds of polymers with very different efficiency are compared. The electron and hole currents are measured in the uni-polar devices and fitted by the theoretical model to get carrier mobilities. The universal features of the high efficiency polymers are that the electron and hole mobilities are comparable and the electron current is larger than the hole current due to the higher hole barriers. The electron current is more crucial than hole current to determine the efficiency in the bipolar light-emitting diode. The purity of polymers and low electron injection barriers both play significant roles in producing stronger electron currents. These results give the physical rules for designing new polymers and the device structures to achieve highly electroluminescent devices. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.
InGaAs quantum-well saturable absorbers for a diode-pumped passively Q-switched Nd : YAG laser at 1123 nm
(2007-01-10)
Huang, J. Y.
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Liang, H. C.
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Su, K. W.
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Lai, H. C.
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Chen, Y. -F.
A low-loss semiconductor saturable absorber based on InGaAs quantum wells was developed for highly efficient Q switching of a diode-pumped Nd:YAG laser operating at 1123 nm. With an incident pump power of 16 W, an average output power of 3.1 W with a Q-switched pulse width of 77 ns at a pulse repetition rate of 100 kHz was obtained. (c) 2007 Optical Society of America.
Passively Q-switched Yb3+: YCa4O(BO3)(3) laser with InGaAs quantum wells as saturable absorbers
(2007-04-20)
Liang, H. C.
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Huang, J. Y.
;
Su, K. W.
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Lai, H. C.
;
Chen, Y. F.
A diode-pumped Yb:YCOB laser at 1086 nm is passively Q switched by using InGaAs quantum wells as saturable absorbers and utilizing the Bragg mirror structure as an output coupler. With an absorbed pump power of 9.2 W the laser produces pulses of 100 ms duration with average pulse energy of as much as 165 mu J at a pulse repetition rate of 7 kHz. (c) 2007 Optical Society of America.