Search

Position‐sensitive detectors (PSDs) are widely used in optical inspection applications, such as precise measurement of distance and angle, surface profiling, and motion tracking, etc. The lateral photovoltaic effect is the mechanism employed by most PSDs to determine position, but its gain‐free nature hinders weak‐light detection and applications. Here, a new position recognition mechanism with an intrinsic high gain is proposed and employ it to design a weak‐light and large‐size photoconductor‐type PSD. The position recognition is established by the intrinsic link between the gain and channel length in a photoconductor, and the designed linear correlation between the channel length and position. The photoconductor‐type graphene/Si PSD based on the recognition mechanism shows an active length of over 1 mm, a high spatial position resolution at the sub‐micrometer level, and a low detection limit power of 100 pW. Compared with Si PSDs, the gain of the photoconductor‐type PSD is improved by 3–4 orders of magnitude. In addition, the operational wavelength range of the PSD is expanded to include the near‐infrared region, specifically at 1300 and 1550 nm. The new position recognition mechanism paves the way for the development of ultra‐sensitive light position detection. [ABSTRACT FROM AUTHOR]

In this paper, a hybrid numerical technique is presented for modeling a photoconducting antenna structure designed for optoelectronic generation of millimeter waves. The technique interfaces the solid-state device model with the three-dimensional (3D) finite-difference time-domain (FDTD) method to achieve the active antenna modeling effectiveness and efficiency. The FDTD algorithm is applied to simulate the passive part of the antenna structure, whereas the numerical device simulation is employed to model the photoconductor that is illuminated by lasers. Physical performance of the photoconductor and response of the antenna are analyzed. Numerical results show good correlation with the experimental result and consequently demonstrate the feasibility of the full-wave modeling. © 2000 John Wiley & Sons, Inc. Int J RF and Microwave CAE 10: 213–220, 2000. [ABSTRACT FROM AUTHOR]

In this article the theoretical analysis concerning photo-conducting antennas is made with the use of time-resolved Maxwell equations associated with a drift diffusion model for photoconductor behavior. This method will be applied to the study of particular antennas in order to see the influence of the electrodes on their response and therefore to predict the influence of the photoconductor environment on the radiated field. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 15: 110–113, 1997. [ABSTRACT FROM AUTHOR]

The FDTD method is applied for the theoretical analysis of a new pulse-forming optoelectronic device. Because of a capacitive structure, a photoconductive pulse characterized by a fast rise and a long tail, is derived and provides an ultrashort electrical pulse. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 14: 240–244, 1997 [ABSTRACT FROM AUTHOR]

An experimental high resolution radar imaging technique is described. which permits magnitude determination of currents and local fields established on an around complex bodies irradiated with microwave energy. This highly useful information reveals radar cross section contributions from constituent parts of larger systems. [ABSTRACT FROM AUTHOR]

An optically controlled microwave attenuator is described. The bulk semiconductor properties of cadmium selenide are demonstrated effectively at Ku band frequencies. The device is configured monolithically with a low capacitance resistive channel. Electrical resonance is achieved with symmetric inductance loops which bridge the channel ends. [ABSTRACT FROM AUTHOR]

In order to increase the output voltages of optoelectronic switches the influence of the gap geometry of these devices on the applicable voltage and the switching efficiency is investigated. It is theoretically shown that electrodes with distinctly rounded corners cause a maximum output signal at a given biased voltage. Experimental results are presented for semicircular and rectangular electrodes. [ABSTRACT FROM AUTHOR]