title: Self-Balancing Position-Sensitive Detector (SBPSD).
abstract: Optical position-sensitive detectors (PSDs) are a non-contact method of tracking the location of a light spot. Silicon-based versions of such sensors are fabricated with standard CMOS technology, are inexpensive and provide a real-time, analog signal output corresponding to the position of the light spot. An innovative type of optical position sensor was developed using two back-to-back connected photodiodes. These so called self-balancing position-sensitive detectors (SBPSDs) eliminate the need for external readout circuitry entirely. Fabricated prototype devices demonstrate linear, symmetric coordinate characteristics and a spatial resolution of 200 μm for a 74 mm device. PSDs are commercially available only up to a length of 37 mm. Prototype devices were fabricated with various lengths up to 100 mm and can be scaled down to any size below that.
authors.affiliation: Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, NY 12222, USA. rporrazzo@albany.edu.
authors.forename: Ryan
authors.initials: R
authors.lastname: Porrazzo
authors.affiliation: Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, NY 12222, USA. llydecker@albany.edu.
authors.forename: Leigh
authors.initials: L
authors.lastname: Lydecker
authors.affiliation: Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, NY 12222, USA. Sgattu@sunycnse.com.
authors.forename: Suhasini
authors.initials: S
authors.lastname: Gattu
authors.affiliation: Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, NY 12222, USA. HBakhru@sunycnse.com.
authors.forename: Hassaram
authors.initials: H
authors.lastname: Bakhru
authors.affiliation: Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, NY 12222, USA. ntokranova@sunycnse.com.
authors.forename: Natalya
authors.initials: N
authors.lastname: Tokranova
authors.affiliation: Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, NY 12222, USA. JCastracane@sunycnse.com.
authors.forename: James
authors.initials: J
authors.lastname: Castracane
keywords: PSD; back-to-back connected photodiode; linear position sensor; optical  position sensor