Wavelength independent normal incident quantum cascade detectors

Arvind P. Ravikumar, Deborah Sivco, Claire F. Gmachl

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


We demonstrate a novel technique for normal-incident absorption in intersubband infrared detectors by taking advantage of light scattering from the side-walls of a wet-etched mesa. We fabricate 'spiral' and 'hairpin' shaped quantum cascade detector at a peak wavelength of 6.6 μm, and compare their performance with a standard rectangular mesa. We achieve a peak responsivity of 6 mA/W for the spiral and 12 mA/W for the hairpin detectors at normal incidence, comparable to the 8.8 mA/W obtained for the mesa at 45 degree incidence. We obtain a background limited detectivity of about 3 × 1010 cm√Hz/W for the spiral and hairpin detectors at 80 K, compared to 3 × 108 cm√Hz/W for the standard mesa. This method to achieve normal incidence absorption is wavelength independent, and does not involve complicated fabrication procedures, paving the way for widespread use of intersubband detectors in sensor applications.

Original languageEnglish (US)
Pages (from-to)25269-25276
Number of pages8
JournalOptics Express
Issue number22
StatePublished - Oct 31 2016

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics


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