Resonant photo acoustic system

摘要

A device includes a resonator having an oscillating portion with dimensions chosen to lead to a desired resonant frequency. A light source is positioned to provide light along the length of the oscillating portion at a specific wave length. A detector detects a change in oscillation of the resonator responsive to the wave pressure produced by the light source heating a gas. The light source is modulated with a frequency the same as the resonant frequency of the resonator.

主权项

1. A device comprising:
a resonator having an oscillating portion formed as a single-prong suspended beam having a supported end; a light source to provide light along a length of the oscillating portion, the light being directed toward the supported end; and a detector to detect a change in oscillation of the resonator responsive to the light source heating a gas, wherein the detector comprises a piezoelectric layer split into two adjacent portions along the length of the single-prong suspended beam supported by a ground electrode, and further comprises a pair of electrodes extending along the lengths of and coupled to respective adjacent portions of the piezoelectric layer, wherein one electrode is positioned to collect positive electrical charges from one portion of the piezoelectric layer and the other electrode is positioned to collect negative electrical charges from the other portion of the piezoelectric layer, such that the adjacent portions along the length of the single-prong suspended beam prevent charge compensation.