Holographic chemical vapor sensor.
A holographic interferometer senses vapor-induced optical path length changes in polymer or other chemically sensitive films. The interferometer is inherently sensitive to changes in chemical vapor content, self-compensates for drifts, and accommodates a large array of sensor elements. A sniff-locked-loop synchronous detection method takes advantage of the interferometer's rapid response to achieve vapor concentration sensitivity in the parts-per-billion (ppb, parts in 10(9)) range. We demonstrate, for example, 40 ppb sensitivity to ethyl alcohol using poly(N-vinyl pyrrolidone) with a measurement time of 5 s.
Ye
Hongke
H
Department of Physics and JILA, National Institute for Standards and Technology, JILA UCB 440, University of Colorado at Boulder, Boulder, Colorado 80309-0440, USA.
Nilsen
Oyvind
O
Bright
Victor M
VM
Anderson
Dana Z
DZ
D004867:Equipment Design; D019544:Equipment Failure Analysis; D000431:Ethanol / Q000032:analysis*; D005740:Gases / Q000032:analysis*; D006696:Holography / Q000295:instrumentation* / Q000379:methods; D007368:Interferometry / Q000295:instrumentation* / Q000379:methods; D008832:Microchemistry / Q000295:instrumentation* / Q000379:methods; D014159:Transducers
D005740:Gases; D000431:Ethanol