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556 results on '"Sadwick, Laurence P."'

27. A novel terahertz detector technology based on vacuum electronics

Author

Sadwick, Laurence P., Yang, Tianxin, Kawai, Naoya, Buchmann, Tobias Olaf, Takahashi, Hisanari, Katsuyama, Kota, Lange, Simon Jappe, Sebek, Matej, Jepsen, Peter Uhd, Satozono, Hiroshi, Ohmura, Takayuki, Sadwick, Laurence P., Yang, Tianxin, Kawai, Naoya, Buchmann, Tobias Olaf, Takahashi, Hisanari, Katsuyama, Kota, Lange, Simon Jappe, Sebek, Matej, Jepsen, Peter Uhd, Satozono, Hiroshi, and Ohmura, Takayuki

Abstract

A THz detector with both high sensitivity and fast time response has been required for industrial applications such as nondestructive testing (NDT), security, and spectroscopy. Through a collaboration with the Technical University of Denmark (DTU), we have recently developed a THz-sensitive point detector and imager based on metasurface and photomultiplier tube (PMT) and image intensifier (I.I.) technologies, respectively. A fast time response is one of the unique characteristics of these devices: the PMT-based point detector provides a nanosecond response time while the I.I.based imager is capable of frame rates up to 1000 fps. These devices have a double split-ring resonator (DSRR) at the photocathode for THz-electron conversion (metasurface). In this paper, we discuss the two devices and report on the development and results for increasing their sensitivity for ultrafast, broadband THz pulses by sharpening the field-enhancing antenna tips. This leads to a smaller tip diameter, which increases the electric field confinement and thus intensity at the tip, making the field emission more likely to occur at lower field strengths as a result. Both devices thus offer a sensitive and simple method to detect THz frequencies easily, with the I.I. offering a handheld, 9V battery-powered device.

Published
2023

41. Molecular beam epitaxy growth of TmPGaAs and transistor action in GaP/TmP/GaAs heterostructures

Author

Lin, Ching-Hsi, Hwu, R. Jennifer, Sadwick, Laurence P., and Heo, Dongho

Subjects
Gallium arsenide -- Research, Diodes, Schottky-barrier -- Research, Transistors -- Research, Business, Electronics, Electronics and electrical industries
Abstract

Growth of thulium phosphide (TmP) by molecular-beam epitaxy (MBE) on GaAs substrate is examined. Good epilayer quality is shown, using X-ray diffraction (XRD), atomic force micoscopy (AFM) and transmission electron microscopy (TEM) analysis.

Published
2001

42. 500(deg)C electronics for harsh environments

Author

Sadwick, Laurence P, Hwu, R. Jennifer, Chern, J. H. Howard, Lin, Ching-Hsu, Castillo, Linda Del, and Johnson, Travis

Abstract

Solid state vacuum devices (SSVDs) are a relatively new class of electronic devices. Innosys is a leading producer of high frequency SSVDs for a number of applications, including RF communications. SSVDs combine features inherent to both solid state and vacuum transistors. Electron transport can be by solid state or vacuum or both. The focus of this talk is on thermionic SSVDs, in which the primary vacuum transport is by thermionically liberated electron emission.

Published
2005

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