VOLTAGE-BIASED SUPERCONDUCTING TRANSITION-EDGE BOLOMETER WITH STRONG ELECTROTHERMAL FEEDBACK OPERATED AT 370 MK

Citation
Sf. Lee et al., VOLTAGE-BIASED SUPERCONDUCTING TRANSITION-EDGE BOLOMETER WITH STRONG ELECTROTHERMAL FEEDBACK OPERATED AT 370 MK, Applied optics, 37(16), 1998, pp. 3391-3397
Citations number
12
Categorie Soggetti
Optics
Journal title
ISSN journal
00036935
Volume
37
Issue
16
Year of publication
1998
Pages
3391 - 3397
Database
ISI
SICI code
0003-6935(1998)37:16<3391:VSTBWS>2.0.ZU;2-S
Abstract
We present an experimental study of a composite voltage-biased superco nducting bolometer (VSB). The tested VSB consists of a Ti-film superco nducting thermometer (T-c similar to 375 mK) on a Si substrate suspend ed by NbTi superconducting leads. A resistor attached to the substrate provides calibrated heat input into the bolometer. The current throug h the bolometer is measured with a superconducting quantum interferenc e device ammeter. Strong negative electrothermal feedback fixes the bo lometer temperature at T, and reduces the measured response time from 2.6 s to 13 ms. As predicted, the measured current responsivity of the bolometer is equal to the inverse of the bias voltage. A noise equiva lent power of 5 x 10(-17) W/root Hz was measured for a thermal conduct ance G similar to 4.7 x 10(-10) W/K, which is consistent with the expe cted thermal noise. Excess noise was observed for bias conditions for which the electrothermal feedback strength was close to maximum. (C) 1 998 Optical Society of America.