| abstract |
The sensor measures diffusion of a fluorescent marker in cavities. The sensor has a Mach-Zehnder micro-interferometer having a reference arm and a measurement arm. The reference arm has a deposit of a sensitive layer whose refractive index is modified when the sensitive layer is in contact with the fluorescent marker. In one embodiment, the micro-interferometer has a diode laser configured to generate a source beam, a substrate of silicon micro-machined with two Y junctions, where a first Y junction is configured to divide the source beam into a measurement beam along the measurement arm and a reference beam along the reference arm, a piezo-electric transducer configured to shift the frequency of the reference beam in phase by an acoustic modulation, wherein a second Y junction combines the measurement bean and the shifted reference beam to generate a combined beam; and a photo-detector configured to detect the combined beam. In one application, the sensor is used for in situ assessment of bronchial capillary permeability. |