We theoretically explore the tunability of optomechanically induced transparency(OMIT)phenomenon and fast-slow light effect in a loop-coupled hybrid optomechanical system in which two optical modes are coupled to a co...We theoretically explore the tunability of optomechanically induced transparency(OMIT)phenomenon and fast-slow light effect in a loop-coupled hybrid optomechanical system in which two optical modes are coupled to a common mechanical mode.In the probe output spectrum,we find that the interference phenomena OMIT caused by the optomechanical interactions and the normal mode splitting(NMS)induced by the strong tunnel coupling between the cavities can be observed.We further observe that the tunnel interaction will affect the distance and the heights of the sideband absorption peaks.The results also show that the switch from absorption to amplification can be realized by tuning the driving strength because of the existence of stability condition.Except from modulating the tunnel interaction,the conversion between slow light and fast light also can be achieved by adjusting the optomechanical interaction in the output field.This study may provide a potential application in the fields of high precision measurement and quantum information processing.展开更多
Transition metal dichalcogenides(TMDCs) belong to a subgroup of two-dimensional(2 D) materials which usually possess thickness-dependent band structures and semiconducting properties. Therefore, for TMDCs to be widely...Transition metal dichalcogenides(TMDCs) belong to a subgroup of two-dimensional(2 D) materials which usually possess thickness-dependent band structures and semiconducting properties. Therefore, for TMDCs to be widely used in electronic and optoelectronic applications, two critical issues need to be addressed, which are thickness-controllable fabrication and doping modulation of TMDCs. In this work, we successfully obtained monolayer WS2 and achieved its efficient doping by chemical vapor deposition and chemical doping, respectively. The n-and p-type dopings of the monolayer WS2 were achieved by drop coating electron donor and acceptor solutions of triphenylphosphine(PPh3) and gold chloride(AuCl_3), respectively, on the surface, which donates and captures electrons to/from the WS2 surface through charge transfer, respectively. Both doping effects were investigated in terms of the electrical properties of the fabricated field effect transistors. After chemical doping, the calculated mobility and density of electrons/holes are around 74.6/39.5 cm^2 · V^(-1) ·s^(-1)and 1.0 x 10^(12)/4.2 x 10^(11) cm^(-2), respectively. Moreover, we fabricated a lateral WS2 p-n homojunction consisting of nondoped n-type and p-doped p-type regions, which showed great potential for photodetection with a response time of 1.5 s and responsivity of 5.8 A/W at V_G = 0 V and V_D = 1 V under 532 nm light illumination.展开更多
公路洒落物是影响交通安全的重要因素之一,为了解决中小尺度公路洒落物检测中的漏检、误检以及难以定位等问题,本文提出了一种图像引导和点云空间约束的公路洒落物检测定位方法。该方法使用改进的YOLOv7-OD网络处理图像数据获取二维目...公路洒落物是影响交通安全的重要因素之一,为了解决中小尺度公路洒落物检测中的漏检、误检以及难以定位等问题,本文提出了一种图像引导和点云空间约束的公路洒落物检测定位方法。该方法使用改进的YOLOv7-OD网络处理图像数据获取二维目标预测框信息,将目标预测框投影到激光雷达坐标系下得到锥形感兴趣区域(region of interest,ROI)。在ROI区域内的点云空间约束下,联合点云聚类和点云生成算法获得不同尺度的洒落物在三维空间中的检测定位结果。实验表明:改进的YOLOv7-OD网络在中尺度目标上的召回率和平均精度分别为85.4%和82.0%,相比YOLOv7网络分别提升6.6和8.0个百分点;在小尺度目标上的召回率和平均精度分别为66.8%和57.3%,均提升5.3个百分点;洒落物定位方面,对于距离检测车辆30~40 m处的目标,深度定位误差为0.19 m,角度定位误差为0.082°,实现了多尺度公路洒落物的检测和定位。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.62061028)the Foundation for Distinguished Young Scientists of Jiangxi Province,China(Grant No.20162BCB23009)+2 种基金the Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics(Grant No.KF202010)the Interdisciplinary Innovation Fund of Nanchang University(Grant No.9166-27060003-YB12)the Open Research Fund Program of the Key Laboratory of Opto-Electronic Information Acquisition and Manipulation of Ministry of Education(Grant No.OEIAM202004).
文摘We theoretically explore the tunability of optomechanically induced transparency(OMIT)phenomenon and fast-slow light effect in a loop-coupled hybrid optomechanical system in which two optical modes are coupled to a common mechanical mode.In the probe output spectrum,we find that the interference phenomena OMIT caused by the optomechanical interactions and the normal mode splitting(NMS)induced by the strong tunnel coupling between the cavities can be observed.We further observe that the tunnel interaction will affect the distance and the heights of the sideband absorption peaks.The results also show that the switch from absorption to amplification can be realized by tuning the driving strength because of the existence of stability condition.Except from modulating the tunnel interaction,the conversion between slow light and fast light also can be achieved by adjusting the optomechanical interaction in the output field.This study may provide a potential application in the fields of high precision measurement and quantum information processing.
基金Project supported by the National Natural Science Foundation of China(Grant No.21405109)Seed Foundation of State Key Laboratory of Precision Measurement Technology and Instruments,China(Grant No.1710)
文摘Transition metal dichalcogenides(TMDCs) belong to a subgroup of two-dimensional(2 D) materials which usually possess thickness-dependent band structures and semiconducting properties. Therefore, for TMDCs to be widely used in electronic and optoelectronic applications, two critical issues need to be addressed, which are thickness-controllable fabrication and doping modulation of TMDCs. In this work, we successfully obtained monolayer WS2 and achieved its efficient doping by chemical vapor deposition and chemical doping, respectively. The n-and p-type dopings of the monolayer WS2 were achieved by drop coating electron donor and acceptor solutions of triphenylphosphine(PPh3) and gold chloride(AuCl_3), respectively, on the surface, which donates and captures electrons to/from the WS2 surface through charge transfer, respectively. Both doping effects were investigated in terms of the electrical properties of the fabricated field effect transistors. After chemical doping, the calculated mobility and density of electrons/holes are around 74.6/39.5 cm^2 · V^(-1) ·s^(-1)and 1.0 x 10^(12)/4.2 x 10^(11) cm^(-2), respectively. Moreover, we fabricated a lateral WS2 p-n homojunction consisting of nondoped n-type and p-doped p-type regions, which showed great potential for photodetection with a response time of 1.5 s and responsivity of 5.8 A/W at V_G = 0 V and V_D = 1 V under 532 nm light illumination.
文摘公路洒落物是影响交通安全的重要因素之一,为了解决中小尺度公路洒落物检测中的漏检、误检以及难以定位等问题,本文提出了一种图像引导和点云空间约束的公路洒落物检测定位方法。该方法使用改进的YOLOv7-OD网络处理图像数据获取二维目标预测框信息,将目标预测框投影到激光雷达坐标系下得到锥形感兴趣区域(region of interest,ROI)。在ROI区域内的点云空间约束下,联合点云聚类和点云生成算法获得不同尺度的洒落物在三维空间中的检测定位结果。实验表明:改进的YOLOv7-OD网络在中尺度目标上的召回率和平均精度分别为85.4%和82.0%,相比YOLOv7网络分别提升6.6和8.0个百分点;在小尺度目标上的召回率和平均精度分别为66.8%和57.3%,均提升5.3个百分点;洒落物定位方面,对于距离检测车辆30~40 m处的目标,深度定位误差为0.19 m,角度定位误差为0.082°,实现了多尺度公路洒落物的检测和定位。