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Subpicosecond Optical Sampling Gate

IP.com Disclosure Number: IPCOM000062058D
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Van Zeghbroeck, BJ: AUTHOR

Abstract

The transistor-like sampling gate structure with emitter, base and collector electrodes comprises two potential barriers (emitter-base and base-collector). The signal to be measured is applied to the emitter and affects the effective height of the base-collector barrier. A short optical sampling pulse causes electrons in the emitter to be excited. They gain sufficient energy to be injected across the emitter-base barrier into the base region. Only those electrons with a large enough energy can traverse the base-collector barrier. The device distinguishes between electrons with different energies. Fig. 1 shows the band diagram of the sampling gate.

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Subpicosecond Optical Sampling Gate

The transistor-like sampling gate structure with emitter, base and collector electrodes comprises two potential barriers (emitter-base and base-collector). The signal to be measured is applied to the emitter and affects the effective height of the base-collector barrier. A short optical sampling pulse causes electrons in the emitter to be excited. They gain sufficient energy to be injected across the emitter-base barrier into the base region. Only those electrons with a large enough energy can traverse the base-collector barrier. The device distinguishes between electrons with different energies. Fig. 1 shows the band diagram of the sampling gate. By applying a light (sampling) pulse, electrons at the emitter are excited to an energy level hn which enables them to overcome the emitter-base barrier and to reach the base region. The electrons pass through the base region, and those with a sufficiently high energy cross the second potential barrier and are collected in the collector region. Electrons with lower energy are stopped by the second barrier, fall into the base region and leave the device at the base contact. Applying voltage signals VEB between emitter and base leads to variations of the height of the second barrier, i.e., the device can be used to sample signals that are applied to the emitter provided the signals are properly synchronized with the light pulse used to excite the electrons. The dotted curve illustrates the curve shift and the resulting change in barrier height obtained when applying a voltage VEB . Fig. 2 shows a possible structure of the device. It includes, for a complete sampling...