Abstract-The operation principle of resonant channel add-drop filters based on degenerate symmetric and antisymmetric standing-wave modes has been described elsewhere using group theoretical arguments. In this paper, the analysis is carried out using coupling of modes in time. A possible implementation of such a filter is a four-port system utilizing a pair of identical single-mode standing wave resonators. The analysis allows a simple derivation of the constraints imposed on the design parameters in order to establish degeneracy. Numerical simulations of wave propagation through such a filter are also shown, as idealized by a two-dimensional geometry.
We investigate general channel drop tunneling processes using both analytic theory and first-principles simulations. These tunneling processes occur when two one-dimensional continuums are brought into close proximity with a resonator system that supports localized states. Propagating states can be transferred between the continuums through the resonator system. We show that the transport properties are intricately related to the symmetries of the resonant states. Complete transfer can be achieved by manipulating the symmetries of the system, and by forcing an accidental degeneracy between states with different symmetries. In addition, the line shape of the transfer spectrum can be engineered by varying the number of localized states in the resonator system. The theoretical analysis is confirmed by first-principles simulations of transport properties in a twodimensional photonic crystal. ͓S0163-1829͑99͒09419-9͔ PRB 59 SHANHUI FAN et al.
We describe and demonstrate sensitive room-temperature detection of terahertz (THz) radiation by nonlinearly upconverting terahertz to the near-infrared regime, relying on telecommications components. THz radiation at 700 GHz is mixed with pump light at 1550 nm in a bulk GaAs crystal to generate an idler wave at 1555.6 nm, which is separated and detected by using a commercial p-i-n diode. The THz detector operates at room temperature and has an intrinsic THz-to-optical photon conversion efficiency of 0.001%.
Autonomous vehicles are revolutionizing transport and next-generation autonomous mobility. Such vehicles are promising to increase road safety, improve traffic efficiency, reduce vehicle emission, and improve mobility. However, for these vehicles to live up to their full potentials, there are significant research, technological and urgent organizational issues that need to be addressed to reach the highest level of automation, i.e., level 5. Sensors, communication, mobile edge computing, machine learning, data analytic, distributed learning, and so on, are examples of the building blocks technologies and concepts constituting the end-to-end solution. This survey discusses these technologies and concepts and maps their roles to the end-to-end solution. It highlights the challenges for each technology. Moreover, this survey provides an analysis of different solution approaches proposed by relevant stakeholders, utilizing these technologies aiming to achieve level-5 autonomy. Finally, the article details two use cases to present the interplay of the building blocks technologies.
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