Browsing by Author "Lai, YF"

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Automatically controlled power equalizer for liquid crystal based optical demultiplexer
(2005)
Lan, YP
;
Lai, YF
;
Pan, RP
;
Pan, CL
;
交大名義發表
Power equalization of four channels for a liquid crystal based demultiplexer by automatically controlling the liquid crystal pixels is demonstrated. The variation between different channels reduced from 10 dB to 0.15 dB.
Emission of bright blue light from mesoporous silica with dense Si (Ge) nanocrystals
(2005)
Cho, AT
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Shieh, JM
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Shieh, J
;
Lai, YF
;
Dai, BT
Three-dimensional Si (Ge) nanocrystals (NCs) were dispersed within the nanopores of mesoporous silica films by high-density plasma (HDP), low-density plasma, or implantation. Surface states of the resulting Si (Ge) NCs/silica arrays initiate blue-white photoluminescence (PL). HDP makes reactive species highly mobile and enables deposited NCs bonded with pore-wall well, therefore, efficiently constructing photoemission arrays. The mean density of HDP-synthesized semiconducting NCs is as high as 1 x 10(18)/cm(3). Accordingly, blue PL of arrays obtained with HDP, which is 4- 7 times stronger than those obtained with other methods, exhibits quantum-efficiency of 1%, near the reported value for green-to-red light emission from quantum-confined Si NCs. © 2005 The Electrochemical Society. All rights reserved.
Low-temperature fabrication of carbon nanofibers by self-assembling of polycyclic aromatic hydrocarbon molecules
(2004-04-19)
Suen, SC
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Whang, WT
;
Wu, BW
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Lai, YF
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材料科學與工程學系
Carbon nanofibers (CNFs) with diameter similar to66 nm have been synthesized from coronene by low-temperature (similar to45 degreesC) vacuum sublimation without the aid of a catalyst. Our method makes use of the property of polycyclic aromatic hydrocarbon (PAH) molecules, which can self-assemble into columnar aggregates. This polycyclic aromatic hydrocarbon-carbon nanofibers (PAH-CNFs) reveal much better thermal stability than commercial carbon nanotubes and exhibit field-emission characteristics with the onset of an electric field of 5.4 V/mum and field enhancement factor of 1326 cm(-1) for 100 mum interelectrode distance. The relative high thermal stability and easier process open up a possibility to fabricate large-scale field-emission devices in an efficient way and to provide a broad range of applications in nanoscience and technology. (C) 2004 American Institute of Physics.
Multimode optical demultiplexer for DWDM with liquid crystal enabled functionalities
(2004-10-01)
Huang, MJ
;
Pan, RP
;
Sheu, CR
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Lan, YP
;
Lai, YF
We have developed a liquid-crystal-based multimode optical demultiplexer (DEMUX) with additional functionalities such as switching and power equalization. Demultiplexing 16-channel 100-GHz-spaced signals into a 62.5-mum multimode-fiber array is demonstrated. The central wavelength of each channel is designed according to the International Telecommunication Union grid. Adjacent channel crosstalk is less than -30 dB. The average 1- and 3-dB passbands of the DEMUX are 12.5 and 22.5 GHz, respectively. A maximum extinction ratio of 16.2 dB is achieved. Different channels can be switched with rise and fall times of similar to10 and similar to70 ms, respectively. The outputs of the channels are equalized to -65 dBm. The variation between different channels reduced from similar to10 dB to less than 0.5 dB.
Stable blue luminescence from mesoporous silica films
(2004)
Shieh, JM
;
Cho, AT
;
Lai, YF
;
Dai, BT
;
Pan, FM
This study investigates how blue (similar to 460 nm) photoluminescence (PL) from mesoporous silica (MS) films depends on the nanostructure and chemistry of the pores. Reducing pore-size and pore-wall can increase the total area of the pore-surfaces, and therefore the number of radiative recombination centers, within the MS matrix, enhancing PL efficiency. Moreover, the number of silianol groups on pore-surfaces, which absorb moisture and degrade the PL of the MS films, is greatly reduced by silylating MS with hydrophobicity, yielding long-term stable luminescence. The quantum-efficiency of PL and the electroluminescence of the MS films are measured about 5.0 x 10(-4) and 1.0 x 10(-6), respectively. (C) 2004 The Electrochemical Society.