| Budget Amount *help |
¥26,130,000 (Direct Cost: ¥20,100,000、Indirect Cost: ¥6,030,000)
Fiscal Year 2012: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2011: ¥6,890,000 (Direct Cost: ¥5,300,000、Indirect Cost: ¥1,590,000)
Fiscal Year 2010: ¥16,510,000 (Direct Cost: ¥12,700,000、Indirect Cost: ¥3,810,000)
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| Research Abstract |
A terahertz detector using a superconducting tunnel junction (STJ) coupled to a large terahertz-absorbing superconductor film was investigated. We also proposed a design of a new terahertz detector with transmission-line STJs. The latter detector has two long junctions integrated on both wings of a log-periodic antenna. In this type, the long junction is a high-loss transmission-line working based on the Cooper-pair breaking process, in which the junction length and width determine the absorption efficiency and frequency bandwidth, respectively. A detector using Nb/Al/A1Ox/Al/Nb junctions was fabricated, and the principle of the detector was verified. We have detected terahertz radiation based on the Cooper-pair breaking (CPB), and confirmed that the sensitivity has a gradual increase from 0.35 THz, a value that corresponds to the effective gap frequency of the Nb/Al bilayer. We have also identified the third quarter-wavelength resonance and its harmonic signals working on the photon-assisted tunneling (PAT) process. The STJ detector has the new functionality that both detection processes are available. This functionality will allow the detector to be applied in future THz imaging with wide frequency selectivity.
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