Micro polarizing beam splitter for blue wavelength optical pickups application

Micro polarizing beam splitters (micro PBS) are required in micro optical systems for sensing and signal processing when the polarization state is a concern. In this paper, silicon nitride thin films with low stress and low absorption at 405 nm wavelength were investigated. The reflectance and the transmittance of TM and TE modes of a pop-up micro-PBS composed of a silicon nitride thin film and a poly-silicon frame were examined. Two types of micro PBSs based on low stress silicon nitride were successfully demonstrated. The performance agreed well with calculation. Such devices can be applied for micro optical pickups in data storage systems