We theoretically investigate the characteristics of terahertz(THz) radiation from monolayer graphene exposed to normal incident few-cycle laser pulses, by numerically solving the extended semiconductor Bloch equations...We theoretically investigate the characteristics of terahertz(THz) radiation from monolayer graphene exposed to normal incident few-cycle laser pulses, by numerically solving the extended semiconductor Bloch equations. Our simulations show that the THz spectra in low frequency regions are highly dependent on the carrier envelope phase(CEP) of driving laser pulses. Using an optimal CEP of few-cycle laser pulses, we can obtain broadband strong THz waves, due to the symmetry breaking of the laser-graphene system. Our results also show that the strength of the THz spectra depend on both the intensity and central wavelength of the laser pulses. The intensity dependence of the THz wave can be described by the excitation rate of graphene, while wavelength dependence can be traced back to the band velocity and the population of graphene. We find that a near single-cycle THz pulse can be obtained from graphene driven by a mid-infrared laser pulse.展开更多
The sensing and identification of trace gases are essential for ensuring chemical safety and protecting human health.This study introduces a low-power electronic nose system that utilizes a single sensor driven by rep...The sensing and identification of trace gases are essential for ensuring chemical safety and protecting human health.This study introduces a low-power electronic nose system that utilizes a single sensor driven by repeated pulsed power inputs,offering a viable alternative to conventional sensor array-based methods.The sensor’s compact design and suspended architecture facilitate a rapid thermal response,effectively decoupling the influences of temperature,physisorption,and charge exchange on the conductivity of the sensing material.This mechanism generates distinct gas sensing responses,characterized by alternating dual responses within a single time period.The unique dynamics of the dual signals,which vary with gas type and concentration,enable precise identification of multiple gas species using machine learning(ML)algorithms.Microfabricated through wafer-level batch processing,our innovative electronic nose system holds significant potential for battery-powered mobile devices and IoT-based monitoring applications.展开更多
We systematically study the optimization of highly efficient terahertz（THz） generation in lithium niobate（LN）crystal pumped by 800 nm laser pulses with 30 fs pulse duration. At room temperature, we obtain a record...We systematically study the optimization of highly efficient terahertz（THz） generation in lithium niobate（LN）crystal pumped by 800 nm laser pulses with 30 fs pulse duration. At room temperature, we obtain a record optical-to-THz energy conversion efficiency of 0.43% by chirping the pump laser pulses. Our method provides a new technique for producing millijoule THz radiation in LN via optical rectification driven by joule-level Ti：sapphire laser systems, which deliver sub-50-fs pulse durations.展开更多
With the support by the National Natural Science Foundation of China and the Ministry of Science and Technology of China,Prof.Li Yutong(李玉同)at the Institute of Physics,Chinese Academy of Sciences,in collaboration w...With the support by the National Natural Science Foundation of China and the Ministry of Science and Technology of China,Prof.Li Yutong(李玉同)at the Institute of Physics,Chinese Academy of Sciences,in collaboration with Prof.Zhang Jie(张杰)and Sheng Zhengming(盛政明)at Shanghai Jiao Tong University,demonstrated the generation of high-energy,coherent terahertz(THz)radiation from ultra in-展开更多
基金Supported by the National Natural Science Foundation of China (Grant Nos.11764038,11864037,11765018,and 91850209)。
文摘We theoretically investigate the characteristics of terahertz(THz) radiation from monolayer graphene exposed to normal incident few-cycle laser pulses, by numerically solving the extended semiconductor Bloch equations. Our simulations show that the THz spectra in low frequency regions are highly dependent on the carrier envelope phase(CEP) of driving laser pulses. Using an optimal CEP of few-cycle laser pulses, we can obtain broadband strong THz waves, due to the symmetry breaking of the laser-graphene system. Our results also show that the strength of the THz spectra depend on both the intensity and central wavelength of the laser pulses. The intensity dependence of the THz wave can be described by the excitation rate of graphene, while wavelength dependence can be traced back to the band velocity and the population of graphene. We find that a near single-cycle THz pulse can be obtained from graphene driven by a mid-infrared laser pulse.
基金supported in part by the Guangzhou Municipal Science and Technology Bureau(SL2023A04J00435)in part by the One Hundred Youth Project of Guangdong University of Technology(263113873).
文摘The sensing and identification of trace gases are essential for ensuring chemical safety and protecting human health.This study introduces a low-power electronic nose system that utilizes a single sensor driven by repeated pulsed power inputs,offering a viable alternative to conventional sensor array-based methods.The sensor’s compact design and suspended architecture facilitate a rapid thermal response,effectively decoupling the influences of temperature,physisorption,and charge exchange on the conductivity of the sensing material.This mechanism generates distinct gas sensing responses,characterized by alternating dual responses within a single time period.The unique dynamics of the dual signals,which vary with gas type and concentration,enable precise identification of multiple gas species using machine learning(ML)algorithms.Microfabricated through wafer-level batch processing,our innovative electronic nose system holds significant potential for battery-powered mobile devices and IoT-based monitoring applications.
基金supported by the National Basic Research Program of China(No.2013CBA01501)the National Natural Science Foundation of China(No.11520101003)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDB16010200 and XDB07030300)the "Zhuoyue" Program of Beihang University(No.GZ216S1711)
文摘We systematically study the optimization of highly efficient terahertz（THz） generation in lithium niobate（LN）crystal pumped by 800 nm laser pulses with 30 fs pulse duration. At room temperature, we obtain a record optical-to-THz energy conversion efficiency of 0.43% by chirping the pump laser pulses. Our method provides a new technique for producing millijoule THz radiation in LN via optical rectification driven by joule-level Ti：sapphire laser systems, which deliver sub-50-fs pulse durations.
文摘With the support by the National Natural Science Foundation of China and the Ministry of Science and Technology of China,Prof.Li Yutong(李玉同)at the Institute of Physics,Chinese Academy of Sciences,in collaboration with Prof.Zhang Jie(张杰)and Sheng Zhengming(盛政明)at Shanghai Jiao Tong University,demonstrated the generation of high-energy,coherent terahertz(THz)radiation from ultra in-
