In this paper we present a room-temperature micro-photonic bolometer that is based on the whispering gallery mode of dielectric resonator (WGM). The sensing element is a hollow micro-spherical optical polymeric resonator. The hollow resonator is filled with a fluid (gas or liquid) that has a large thermal expansion. When an incoming radiation impinges on the resonator is absorbed by the absorbing fluid leading to a thermal expansion of the micro-resonator. The thermal expansion induces changes in the morphology of the resonator (size and index of refraction), that in turn lead to a shift of the optical resonances (WGM). The optical resonances are typically excited using a single mode optical fiber. The preliminary analysis presented in this paper, shows that these sensors can measure energies of the order of 0.1J/m2.
In this paper we present a high resolution magnetic field sensor that is based on the perturbation of the optical modes (whispering gallery mode, WGM) of a spherical dielectric resonator. The optical resonator is side coupled to a tapered single mode optical fiber. One side of the optical fiber is coupled to a distribute feedback diode laser, while the other end is connected to a photodiode. The optical modes of the dielectric cavity are perturbed using a metglas sheet that is in contact with the resonator. When the metglas sheet is exposed to an external magnetic field it elongates perturbing the optical modes of the dielectric cavity. This in turn leads to a shift in the optical resonances. By measuring the induced WGM shift the magnetic field can be measured. Preliminary results show sensor resolution of a few nanoteslas.