Patent ID: 8085403
Filing Date: 2011-12-27
Classification: G01N

Abstract:
1. A photoacoustic sensor comprising: an excitation source to generate a monochromatic light; a modulator to intensity modulate the monochromatic light at a first modulation frequency; a quantum dot filter to down convert the modulated monochromatic light into a broadband spectrum of infrared light, which includes a plurality of wavelength components with distinct wavelengths; an interferometer to further intensity modulate the broadband spectrum, wherein at least one of the plurality of wavelength components is further intensity modulated at a second modulation frequency related to a scanning speed of the interferometer and a distinct wavelength of that wavelength component to produce a resultant broadband spectrum of infrared light; a gas chamber to store a sample gas and to receive the resultant broadband spectrum of infrared light; and a microphone coupled to the gas chamber to detect pressure changes within the gas chamber to produce an acoustic signal representative of properties of the sample gas.