Gas refractive index sensor with an integrated prism and a microlens array

A novel sensor for measuring the refractive index of gas is realized by the integration of a prism and a micro-lens array. The proposed sensor is constructed in a single optical path setup and relies on neither a spectrometer nor other spectrum-sensing devices. In the proposed sensor, the gas is injected into the chamber equipped with the prism, and the wavefront of the exit probe beam is decomposed by the microlens array to realize multi-focalization. The developed sensor is utilized to measure the refractive indexes of the air and nitrogen. The refractive index of nitrogen using the proposed sensor is in agreement with data reported previously. By considering twice the standard deviation, a precision of 4.70 x 10-6 RIU is achieved for the refractive index mea-surement of nitrogen

Automated summary

A novel sensor integrating a prism and a micro-lens array is developed for measuring the refractive index of gas. This sensor is constructed in a single optical path setup and does not require a spectrometer or other spectrum-sensing devices. The gas is injected into a chamber equipped with a prism, and the exit probe beam is decomposed by a micro-lens array to achieve multi-focalization. The sensor is used to measure the refractive indexes of air and nitrogen, with the measured refractive index of nitrogen agreeing with previous data. Considering twice the standard deviation, a measurement precision of 4.70 x 10-6 RIU is achieved for nitrogen refractive index measurement.