Optical magnetic field sensor based on guided-mode resonance with Ni subwavelength grating/waveguide structure

摘要

Highly sensitive optical sensor for magnetic field detection was experimentally demonstrated using a guided-moderesonance in waveguide with Ni nano-grating. The electromagnetic field distribution was calculated by finite-differencetime-domain method in order to estimate the sensing performance of our device. The calculation results indicated that theoptical characteristics of our sensor considerably varied with applying magnetic field. We fabricated the Ni-subwavelengthgrating/ Si3N4 waveguide structure on the optical glass substrate using electron beam lithography technique. The reflectionpeak resulting from the guided-mode in the waveguide was obtained with normal incident geometry. The peak intensitydepended on static magnetic field applied to the structure, and the intensity changed by about 5 % for the magnetic fieldintensity of 39.4 mT. These experimental results suggest our sensor can sensitively detect magnetic field while avoidinguse of the complex and expensive system, and our device is pretty suitable for the integration devices in internet of thingssociety.