Brief description for the project:​

In the present project, we are demonstrating the capability of making polydimethylsiloxane (PDMS) microsphere sensors, which take advantage of an optical phenomenon called whispering gallery modes (WGM), a resonance condition happened when the optical path length of a laser in a polymeric microsphere is equal to an integer number of wavelengths, to make extraordinary electric field sensors capable of detecting electric fields. These sensors work by measuring the wavelength at which interference due to WGM occurs and then detecting when this value changes due to a change in the morphology of the spheres. This is possible since PDMS microspheres can be made to physically react to external electric fields. This physical reaction is called the electrostriction effect and governed by Navier’s equation for linear elasticity for steady state case. In this paper, an experiment will be conducted to find the angular orientation effects of the electric field on WGM optical sensors. In this experiment, the electric field is supplied by means of brass plates. These plates are mounted on a servo motor to provide the orientation angle of the applied electric field. The microsphere is placed between the plates. Prior to the experiment, the spheres are subjected to a high strength polling electric field of 1 MV/m. Initial results suggests that the sensitivity of the sphere has a dependence on the angular orientation of the sphere in the sensitizing polling electric field with respect to the orientation in the test electric field. This work we will show a definite relationship between the angular orientation in the sensitizing polling electric field and the response in the test electric field in order to maximize sensitivity. This has direct implications on eventual applications, since the orientation of a future sensor package will directly impact the sensitivity and performance of such a sensor used in the
neurophotonics applications.