A zinc oxide ZnO field emitter-based backlight unit for liquid crystal display with a gated structure is fabricated by screen-printing processes.The measured anode field emission current density reaches 0.62 mA/cm2 wh...A zinc oxide ZnO field emitter-based backlight unit for liquid crystal display with a gated structure is fabricated by screen-printing processes.The measured anode field emission current density reaches 0.62 mA/cm2 when the applied gate voltage is 570 V.Part of the anode current is contributed by the secondary electron emission which is excited from the MgO layer inside the gate apertures on the gate plate. The average emission current density and luminance are 0.47 mA/cm2 and 1 250 cd/m2 respectively with a fluctuation of about 10% during the 1 000 min measurement.By a finite element method calculation the gated structure shows a good electron beam focusing property. The driving performance of the backlight unit is characterized by SPICE simulation tools and measured by the oscilloscope. Stable field emission line-by-line scanning and fast response characteristics of the backlight unit indicate its promising application in the liquid crystal displays.展开更多
Under high-excitation irradiance conditions to induce fluorescence, the dependence of photobleaching of Coumarin 307 （C307） and acriflavine （ACF） laser dyes in liquid and solid phases have been studied. A cw LD la...Under high-excitation irradiance conditions to induce fluorescence, the dependence of photobleaching of Coumarin 307 （C307） and acriflavine （ACF） laser dyes in liquid and solid phases have been studied. A cw LD laser source of 1 mW and 407 nm wavelength was used as an exciting source. For one hour exposure time, it was found that the solid dye samples suffer photobleaching more than the liquid dye samples. This is because in liquid solutions the dye molecules can circulate during the irradiation, while the photobleaching is a serious problem when the dye is incorporated into solid matrix and cannot circulate.展开更多
We propose to generate controllable time delay using slow/fast light in fiber ring resonators with gain manipulation.The dispersion and group delay of active fiber ring resonator can be controlled by manipulating its ...We propose to generate controllable time delay using slow/fast light in fiber ring resonators with gain manipulation.The dispersion and group delay of active fiber ring resonator can be controlled by manipulating its gain level below the lasing threshold.Controllability of the negative group delay in the undercoupled regime and the positive group delay in the overcoupled regime is theoretically demonstrated.Besides,large group delay can be obtained accompanied by signal gain in active ring resonators.In addition,we describe wide bandwidth and large group delay in 4-stage cascaded ring resonators.展开更多
A tunable microwave photonic bandpass filter with high mainlobe-to-sidelobe ratio (MSR) based on a phase modulator and a dispersive device is proposed. The multi-tap characteristics of the filter are realized by slici...A tunable microwave photonic bandpass filter with high mainlobe-to-sidelobe ratio (MSR) based on a phase modulator and a dispersive device is proposed. The multi-tap characteristics of the filter are realized by slicing a broadband source using a Mach-Zehnder interferometer (MZI) which results in a high MSR of 25 dB. The tunability of the filter is realized by an optical variable delay line (OVDL) in one arm of the MZI, which changes the wavelength spacing of the sliced broadband source and results in a tunable free spectrum range (FSR) of the filter. The central frequency of the bandpass filter is tunable from 10.7 GHz to 27 GHz by changing the wavelength spacing from 0.145 nm to 0.054 nm.展开更多
Slowing down velocity and controlling time delay of optical pulses in fiber have many potential applications in optical com-munication systems,and a number of theoretical and experimental studies have been done.In thi...Slowing down velocity and controlling time delay of optical pulses in fiber have many potential applications in optical com-munication systems,and a number of theoretical and experimental studies have been done.In this paper,the transmission spectrum and reflective spectrum of active fiber Bragg grating(FBG)couplers are studied,and the analytic expressions of dispersion and time delay are obtained.By changing the detuning and gain coefficient,different dispersions and time delays in active fiber Bragg grating coupler are obtained.The results show that different detunings and gain coefficients can result in various time delays,and thus tunable time delay could be achieved by changing signal frequency or gain coefficient.展开更多
基金The National Basic Research Program of China(973 Program)(No.2013CB328803)the National Natural Science Foundation of China(No.51002031)+1 种基金the Ph.D.Programs Foundation of Ministry of Education of China(No.20100092120022)the National High Technology Research and Development Program of China(863 Program)(No.2012AA03A302,2013AA011004)
文摘A zinc oxide ZnO field emitter-based backlight unit for liquid crystal display with a gated structure is fabricated by screen-printing processes.The measured anode field emission current density reaches 0.62 mA/cm2 when the applied gate voltage is 570 V.Part of the anode current is contributed by the secondary electron emission which is excited from the MgO layer inside the gate apertures on the gate plate. The average emission current density and luminance are 0.47 mA/cm2 and 1 250 cd/m2 respectively with a fluctuation of about 10% during the 1 000 min measurement.By a finite element method calculation the gated structure shows a good electron beam focusing property. The driving performance of the backlight unit is characterized by SPICE simulation tools and measured by the oscilloscope. Stable field emission line-by-line scanning and fast response characteristics of the backlight unit indicate its promising application in the liquid crystal displays.
文摘Under high-excitation irradiance conditions to induce fluorescence, the dependence of photobleaching of Coumarin 307 （C307） and acriflavine （ACF） laser dyes in liquid and solid phases have been studied. A cw LD laser source of 1 mW and 407 nm wavelength was used as an exciting source. For one hour exposure time, it was found that the solid dye samples suffer photobleaching more than the liquid dye samples. This is because in liquid solutions the dye molecules can circulate during the irradiation, while the photobleaching is a serious problem when the dye is incorporated into solid matrix and cannot circulate.
基金supported by the National Natural Science Foundation of China (Grant No. 61168002)the Provincial Natural Science Foundation of Jiangxi (Grant No. 20132BAB201048)+1 种基金the Science & Technology Project of Science & Technology of Yichun Committee (Grant No. JXYC2013-KGA01)the Opening Foundation of the State Key Laboratory of Advanced Optical Communication Systems and Networks (Grant No.2011GZKF031105)
文摘We propose to generate controllable time delay using slow/fast light in fiber ring resonators with gain manipulation.The dispersion and group delay of active fiber ring resonator can be controlled by manipulating its gain level below the lasing threshold.Controllability of the negative group delay in the undercoupled regime and the positive group delay in the overcoupled regime is theoretically demonstrated.Besides,large group delay can be obtained accompanied by signal gain in active ring resonators.In addition,we describe wide bandwidth and large group delay in 4-stage cascaded ring resonators.
基金supported by the National Natural Science Foundation of China (No.60808004)the New Century Excellent Talents in University (No.NCET-07-0611)the Tianjin Natural Science Foundation (No.08JCYBJC14500)
文摘A tunable microwave photonic bandpass filter with high mainlobe-to-sidelobe ratio (MSR) based on a phase modulator and a dispersive device is proposed. The multi-tap characteristics of the filter are realized by slicing a broadband source using a Mach-Zehnder interferometer (MZI) which results in a high MSR of 25 dB. The tunability of the filter is realized by an optical variable delay line (OVDL) in one arm of the MZI, which changes the wavelength spacing of the sliced broadband source and results in a tunable free spectrum range (FSR) of the filter. The central frequency of the bandpass filter is tunable from 10.7 GHz to 27 GHz by changing the wavelength spacing from 0.145 nm to 0.054 nm.
基金supported by the National Natural Science Foundation of China(No.10704043)the Natural Science Foundation of Zhejiang Province(No.Y1110078)
文摘Slowing down velocity and controlling time delay of optical pulses in fiber have many potential applications in optical com-munication systems,and a number of theoretical and experimental studies have been done.In this paper,the transmission spectrum and reflective spectrum of active fiber Bragg grating(FBG)couplers are studied,and the analytic expressions of dispersion and time delay are obtained.By changing the detuning and gain coefficient,different dispersions and time delays in active fiber Bragg grating coupler are obtained.The results show that different detunings and gain coefficients can result in various time delays,and thus tunable time delay could be achieved by changing signal frequency or gain coefficient.
