The mechanism of terahertz(THz) pulse coherent detection via two-color laser pulses of various frequency ratios in gas plasma is theoretically investigated.Our investigations demonstrate that except for the commonly u...The mechanism of terahertz(THz) pulse coherent detection via two-color laser pulses of various frequency ratios in gas plasma is theoretically investigated.Our investigations demonstrate that except for the commonly used frequency ratio of 2, other uncommon frequency ratios can also be utilized to detect THz pulse, such as 2 n, n + 1/2(n ≤ 3, n is a positive integer).The well-developed transient photocurrent model is extended to our terahertz detection process.Based on this model, our simulation results can be explained by analyzing the process of asymmetric electron ionization and electron acceleration.展开更多
The mechanism of terahertz(THz)pulse generation with a static magnetic field imposed on a gas plasma is theoretically investigated.The investigation demonstrates that the static magnetic field alters the electron moti...The mechanism of terahertz(THz)pulse generation with a static magnetic field imposed on a gas plasma is theoretically investigated.The investigation demonstrates that the static magnetic field alters the electron motion during the optical field ionization of gas,leading to a two-dimensional asymmetric acceleration process of the ionized electrons.Simulation results reveal that elliptically or circularly polarized broadband THz radiation can be generated with an external static magnetic field imposed along the propagation direction of the two-color laser.The polarization of the THz radiation can be tuned by the strength of the external static magnetic field.展开更多
Previous research shows that few-cycle laser（FCL） pulses with low energy and without a bias field can be used to coherently detect terahertz（THz） pulses. As we know, it is very difficult to stabilize the carrier e...Previous research shows that few-cycle laser（FCL） pulses with low energy and without a bias field can be used to coherently detect terahertz（THz） pulses. As we know, it is very difficult to stabilize the carrier envelope phase（CEP） of FCL pulses, i.e., there are some random fluctuations for the CEP. Here we theoretically investigate the influence of such instability on the accuracy of THz detection. Our results show that although there is an optimum CEP for THz detection, the fluctuations of the CEP will lead to terrible thorns on the detected THz waveform. In order to solve this problem, we propose an approach using two few-cycle laser pulses with opposite CEPs, i.e., their CEPs are differed by π.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11574105,61475054,and 61405063)
文摘The mechanism of terahertz(THz) pulse coherent detection via two-color laser pulses of various frequency ratios in gas plasma is theoretically investigated.Our investigations demonstrate that except for the commonly used frequency ratio of 2, other uncommon frequency ratios can also be utilized to detect THz pulse, such as 2 n, n + 1/2(n ≤ 3, n is a positive integer).The well-developed transient photocurrent model is extended to our terahertz detection process.Based on this model, our simulation results can be explained by analyzing the process of asymmetric electron ionization and electron acceleration.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11574105,and 61475054)the Fundamental Research Funds for the Central Universities,China(Grant No.2017KFYXJJ029)
文摘The mechanism of terahertz(THz)pulse generation with a static magnetic field imposed on a gas plasma is theoretically investigated.The investigation demonstrates that the static magnetic field alters the electron motion during the optical field ionization of gas,leading to a two-dimensional asymmetric acceleration process of the ionized electrons.Simulation results reveal that elliptically or circularly polarized broadband THz radiation can be generated with an external static magnetic field imposed along the propagation direction of the two-color laser.The polarization of the THz radiation can be tuned by the strength of the external static magnetic field.
基金supported by the National Natural Science Foundation of China(Nos. 61475054 and 11574105)the Fundamental Research Funds for the Central Universities (No. 2017KFYXJJ029)
文摘Previous research shows that few-cycle laser（FCL） pulses with low energy and without a bias field can be used to coherently detect terahertz（THz） pulses. As we know, it is very difficult to stabilize the carrier envelope phase（CEP） of FCL pulses, i.e., there are some random fluctuations for the CEP. Here we theoretically investigate the influence of such instability on the accuracy of THz detection. Our results show that although there is an optimum CEP for THz detection, the fluctuations of the CEP will lead to terrible thorns on the detected THz waveform. In order to solve this problem, we propose an approach using two few-cycle laser pulses with opposite CEPs, i.e., their CEPs are differed by π.
