Open AccessOptical and infrared detection using microcantilevers
Author(s) -
P. I. Oden,
Panos G. Datskos,
R. J. Warmack,
E A Wachter,
Thomas Thundat
Publication year - 1996
Language(s) - English
Resource type - Reports
DOI - 10.2172/238545
Subject(s) - infrared , noise equivalent power , materials science , piezoresistive effect , cantilever , optoelectronics , diode , noise (video) , irradiation , laser , bending , thermal resistance , quantum dot , thermal , optics , analytical chemistry (journal) , responsivity , photodetector , physics , composite material , chemistry , meteorology , computer science , nuclear physics , image (mathematics) , chromatography , artificial intelligence
The feasibility of micromechanical optical and infrared (IR) detection using microcantilevers is demonstrated. Microcantilevers provide a simple means for developing single- and multi-element sensors for visible and infrared radiation that are smaller, more sensitive and lower in cost than quantum or thermal detectors. Microcantilevers coated with a heat absorbing layer undergo bending due to the differential stress originating from the bimetallic effect. Bending is proportional to the amount of heat absorbed and can be detected using optical or electrical methods such as resistance changes in piezoresistive cantilevers. The microcantilever sensors exhibit two distinct thermal responses: a fast one ({theta}{sub 1}{sup thermal} < ms) and a slower one ({tau}{sub 2}{sup thermal} {approximately} 10 ms). A noise equivalent temperature difference, NEDT = 90 mK was measured. When uncoated microcantilevers were irradiated by a low-power diode laser ({lambda} = 786 nm) the noise equivalent power, NEP, was found to be 3.5nW/{radical}Hz which corresponds to a specific detectivity, D*, of 3.6 {times} 10{sup 7} cm {center_dot} {radical}Hz/W at a modulation frequency of 20 Hz