A full-duplex radio-over-fiber system using frequency-twelvefold optical millimeter-wave based on external modulation via a Mach-Zehnder modulator is proposed and analyzed theoretically.The simulation results show tha...A full-duplex radio-over-fiber system using frequency-twelvefold optical millimeter-wave based on external modulation via a Mach-Zehnder modulator is proposed and analyzed theoretically.The simulation results show that the power penalties for both the downstream and upstream signals are iess than 0.5 dB.In this scheme,the configuration of a base station is simplified without laser,while the frequency of local oscillator signal is largely reduced due to the frequency-twelvefold millimeter-wave technique.The cost of the new system is largely reduced.展开更多
We present a novel method for heightening the sensitivity of a prism coupler-based surface plasmon resonance(SPR)sensor.The method is based on the total reflection prism made of BK7 glass combined with the Kretschmann...We present a novel method for heightening the sensitivity of a prism coupler-based surface plasmon resonance(SPR)sensor.The method is based on the total reflection prism made of BK7 glass combined with the Kretschmann geometry of theattenuated total reflection(ATR)method.Compared to the conventional methods of prism coupler-based SPR,the novel method provides higher sensitivity to the measurement system.Theoretical simulations show that the detection sensitivity to the refractive index(RI)of the sensor based on the novel approach has a strong dependence on the thickness of the metal layer.The RI resolution of the sensor is predicted to be 8×10^(-7)refractive index units(RIU)under the condition of optimum metal film thickness.This novel method can leave out a precision angle rotation device in the angle modulation and it is unnecessary to adjust the acceptance angle of the light detector.The principal advantage of this method over other methods of light intensity modulation based on prism coupler-based SPR is high sensitivity,expediency to measure and application of long distances.展开更多
We propose and numerically simulate a nanoscale electro-optic (EO) switch based on a metal-insulator-metal structure composed of a strip waveguide and two side-coupled cavities filled with an EO material of 4-dimethyl...We propose and numerically simulate a nanoscale electro-optic (EO) switch based on a metal-insulator-metal structure composed of a strip waveguide and two side-coupled cavities filled with an EO material of 4-dimethylamino-N-methyl-4-stilbazolium tosylate,using the finite difference time domain method.It is found that the structure can be operated as an EO switch at a wavelength of 945nm,with a modulation depth of 27dB,a half-wave voltage of 5.3 V and a switching time of about 50 ps.展开更多
A high-resolution plasmonic refractive-index sensor based on a metal-insulator-metal structure consisting of a straight bus waveguide and a resonator waveguide is proposed and numerically simulated by using the finite...A high-resolution plasmonic refractive-index sensor based on a metal-insulator-metal structure consisting of a straight bus waveguide and a resonator waveguide is proposed and numerically simulated by using the finite difference time domain method under a perfectly matched layer absorbing boundary condition.Both analytic and simulated results show that the resonant wavelengths of the sensor have a linear relationship with the refractive index of material under sensing.Based on the relationship,the refractive index of the material can be obtained from the detection of one of the resonant wavelengths.The resolution of refractive index of the nanometeric plasmonic sensor can reach as high as 10-6,giving the wavelength resolution of 0.01 nm.It could be applied to highly-resolution biological sensing.展开更多
The fluorescent decays and spectra of pump power density dependent emission demonstrated that the excitation power density was enhanced in Rh640 dye solution containing scattering nanoparticles.Lasing in disordered sc...The fluorescent decays and spectra of pump power density dependent emission demonstrated that the excitation power density was enhanced in Rh640 dye solution containing scattering nanoparticles.Lasing in disordered scattering medium with low threshold,narrow bandwidth,and short duration was observed.The mechanism of this enhancement,together with the lasing properties of low threshold and narrow bandwidth,was discussed.展开更多
We present room temperature femtosecond rejection studies on the photocarrier dynamics of GaAs and GaAs/AlGaAs multiple quantum wells(MQW).A rising wing with a time constant of about.5 ps and an increased amplitude pe...We present room temperature femtosecond rejection studies on the photocarrier dynamics of GaAs and GaAs/AlGaAs multiple quantum wells(MQW).A rising wing with a time constant of about.5 ps and an increased amplitude per carrier is observed for the MQW sample at carrier densities lower than 5×10^(11) cm^(-2).This phenomenon is explained as the saturation of the excitonic transitions.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 61077038.
文摘A full-duplex radio-over-fiber system using frequency-twelvefold optical millimeter-wave based on external modulation via a Mach-Zehnder modulator is proposed and analyzed theoretically.The simulation results show that the power penalties for both the downstream and upstream signals are iess than 0.5 dB.In this scheme,the configuration of a base station is simplified without laser,while the frequency of local oscillator signal is largely reduced due to the frequency-twelvefold millimeter-wave technique.The cost of the new system is largely reduced.
基金Supported by the Science Foundation of North University of China(No 200905)the Natural Science Foundation of Shanxi Education Department(No 20100509zx).
文摘We present a novel method for heightening the sensitivity of a prism coupler-based surface plasmon resonance(SPR)sensor.The method is based on the total reflection prism made of BK7 glass combined with the Kretschmann geometry of theattenuated total reflection(ATR)method.Compared to the conventional methods of prism coupler-based SPR,the novel method provides higher sensitivity to the measurement system.Theoretical simulations show that the detection sensitivity to the refractive index(RI)of the sensor based on the novel approach has a strong dependence on the thickness of the metal layer.The RI resolution of the sensor is predicted to be 8×10^(-7)refractive index units(RIU)under the condition of optimum metal film thickness.This novel method can leave out a precision angle rotation device in the angle modulation and it is unnecessary to adjust the acceptance angle of the light detector.The principal advantage of this method over other methods of light intensity modulation based on prism coupler-based SPR is high sensitivity,expediency to measure and application of long distances.
文摘We propose and numerically simulate a nanoscale electro-optic (EO) switch based on a metal-insulator-metal structure composed of a strip waveguide and two side-coupled cavities filled with an EO material of 4-dimethylamino-N-methyl-4-stilbazolium tosylate,using the finite difference time domain method.It is found that the structure can be operated as an EO switch at a wavelength of 945nm,with a modulation depth of 27dB,a half-wave voltage of 5.3 V and a switching time of about 50 ps.
基金Supported the National Natural Science Foundation of China under Grant No 61077038Natural Science Foundation of Guangdong Province under Grant No 07117866.
文摘A high-resolution plasmonic refractive-index sensor based on a metal-insulator-metal structure consisting of a straight bus waveguide and a resonator waveguide is proposed and numerically simulated by using the finite difference time domain method under a perfectly matched layer absorbing boundary condition.Both analytic and simulated results show that the resonant wavelengths of the sensor have a linear relationship with the refractive index of material under sensing.Based on the relationship,the refractive index of the material can be obtained from the detection of one of the resonant wavelengths.The resolution of refractive index of the nanometeric plasmonic sensor can reach as high as 10-6,giving the wavelength resolution of 0.01 nm.It could be applied to highly-resolution biological sensing.
基金Supported by the National Natural Science Foundation of China under Grant No.19574077the National Reseach Project of 863-416 High Technology,and the Guangdong Natural Science Foundation.
文摘The fluorescent decays and spectra of pump power density dependent emission demonstrated that the excitation power density was enhanced in Rh640 dye solution containing scattering nanoparticles.Lasing in disordered scattering medium with low threshold,narrow bandwidth,and short duration was observed.The mechanism of this enhancement,together with the lasing properties of low threshold and narrow bandwidth,was discussed.
基金Supported by the Science Foundation of Zhongshan University.
文摘We present room temperature femtosecond rejection studies on the photocarrier dynamics of GaAs and GaAs/AlGaAs multiple quantum wells(MQW).A rising wing with a time constant of about.5 ps and an increased amplitude per carrier is observed for the MQW sample at carrier densities lower than 5×10^(11) cm^(-2).This phenomenon is explained as the saturation of the excitonic transitions.
