Patent ID: 8992836
Filing Date: 2015-03-31
Classification: G01N

Abstract:
1. An optofluidic device for measuring an absorption spectrum of an analyte, comprising: a microfluidic channel for containing said analyte; a microresonator positioned at least partially in said microfluidic channel and at least partially immersible in said analyte; a waveguide optically coupled to said microresonator, said waveguide having an input end and an output end, wherein said input end receives a first light signal having a linewidth lesser than the width of at least one resonance of said first light signal propagating in said microresonator, wherein said first light signal is continuously tunable at a rate across a spectrum of wavelengths including one or more wavelengths that define said at least one resonance of said first light signal in said microresonator; a light source that generates said first light signal tunable across said spectrum of wavelengths, wherein said light source outputs said first light signal to said waveguide; and a photo-detector that receives a second light signal exiting said output end of said waveguide, wherein said second light signal at different wavelengths of said spectrum of wavelengths measures the transmission spectrum of said first light signal through said waveguide, said microresonator and said analyte; a mechanism that (1) uses said measured transmission spectrum to determine a total attenuation coefficient and a transmission coefficient by applying a curve fitting to said measured transmission spectrum, wherein said total attenuation coefficient measures the total light absorption caused by said waveguide, said microresonator and said analyte; and (2) obtains a net absorption spectrum resulting from absorption by said analyte by subtracting an intrinsic absorption coefficient from said total absorption coefficient across said spectrum of wavelengths, wherein said intrinsic absorption coefficient measures light absorption caused by said waveguide and said microresonator without presence of said analyte across said spectrum of wavelengths; and a second microresonator positioned at a second coupling distance to said waveguide that is different from a first coupling distance between said microresonator and said waveguide, wherein said microresonator and said second microresonator are used to distinguish said total attenuation coefficient and said transmission coefficient.