2 July 1994 Optically induced inductance modulation of a Nb coil
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Proceedings Volume 2160, Superconductive Devices and Circuits; (1994) https://doi.org/10.1117/12.181002
Event: OE/LASE '94, 1994, Los Angeles, CA, United States
Abstract
We have designed and tested an optically driven inductance modulator, for use as part of a 1/f noise reduction scheme for SQUID magnetometers. The modulated element is a Nb coil photolithographically patterned on a 6x6 mm silicon chip. The coil is covered by three cocentric superconducting washers, patterned from a layer of PbInAu deposited above the Nb. Leads from the washers extend to a meander region directly below an optical fiber, which is coupled to a diode laser. With the laser off, the superconducting washer loops diamanetically shield the coil, and the coil has a low effective inductance. With the laser on, the meander is driven normal and the superconducting washer loops are open, greatly reducing the shielding. The coil then has a high effective inductance. The inductance is measured using a SQUID connected to the coil. Using this method, we have modulated the coil inductance from 2 (mu) H to nearly 20 (mu) H. By using four of these inductance modulators, we plan to fabricate a low- noise chopping network at the input of a SQUID, which can be used to reduce the 1/f noise in SQUID measurements.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Sae Woo Nam, Sae Woo Nam, George S. Park, George S. Park, Blas Cabrera, Blas Cabrera, Martin E. Huber, Martin E. Huber, } "Optically induced inductance modulation of a Nb coil", Proc. SPIE 2160, Superconductive Devices and Circuits, (2 July 1994); doi: 10.1117/12.181002; https://doi.org/10.1117/12.181002
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