Sensitivity improvement on CW dual-wavelength photoacoustic spectroscopy using acoustic resonant mode for noninvasive glucose monitor

A technique to improve sensitivity of the CW photoacoustic spectroscopy has been developed and verified by measuring absorbance of water at different temperatures. The technique utilizes coupling between acoustic standing waves or acoustic resonant modes and the photoacoustic source distribution in the sample. By choosing proper acoustic resonant mode, the sensitivity can be enhanced approximately fivefold. The results imply that the method can be applied to low levels of glucose for non-invasive monitoring.