Voltage controllable Goos Hänchen and Imbert Fedorov shifts based on capacitor structure

Abstract

The polarization properties and optical spot position of a 1550 nm linearly polarized laser beam reflected from ITO-Au(100 nm)/Ti(30 nm) interdigital electrodes-SiO2 glass (ITO-IE) or ITO-SiO2 microspheres-Au(100 nm)/Ti(30 nm) interdigital electrodes-SiO2 glass (ITO-SiO2-IE) are studied by a Thorlabs PAX 5710 IR3 polarimeter and a Thorlabs BP209-IR slit beam profiler detector under external direct current (DC) voltage. The Au is used as a reflective layer and the Ti is used as a buffer layer. The Au/Ti interdigital electrodes are prepared on SiO2 glass by thick film, printed circuit board and MEMS process. The surface morphology of the ITO-IE and ITO-SiO2-IE is obtained by a polarized light microscope. The polarization parameters' change of the linearly polarized laser beam reflected from ITO-IE is larger than that of the ITO-SiO2-IE. The maximum Goos Hänchen (GH) and Imbert Fedorov (IF) shifts of the linearly polarized laser beam reflected from the ITO-IE are 135.79 μm and −127.7 μm, while the GH and IF shifts of the linearly polarized laser beam reflected from ITO-SiO2-IE are 96.75 μm and −103.48 μm, when the external DC voltage increases from 0 to 3.0 V. The polarization properties and spatial position of the linearly polarized laser beam reflected from the ITO-IE and ITO-SiO2-IE capacitors show different trends. It is very important for the manufacture and design of optical displacement sensors.