A beam position sensor for low power infrared laser diodes

Year: 1999

Authors: Capineri L., Masotti L., Mazzoni M., Toci G., Mazzinghi P.

Autors Affiliation: Dipartimento Ingegneria Elettronica, Via S. Marta Firenze, Italy; Istituto di Elettronica Quantistica, Via Panciatichi 56/30 50127 Firenze, Italy; Istituto Nazionale di Ottica, Largo E. Fermi 6, 50125 Firenze, Italy

Abstract: This article presents the design criteria, the prototype development, and application results of a low-cost four quadrants infrared (IR) detector. The detector was specifically developed as a position sensor for the alignment of low power IR laser diode beams, especially for spectroscopic applications. The detector consists of a polyvinilidene difluoride pyroelectric radiation sensor of 4 x 4 mm(2) total surface area and of a four-channel high gain transimpedance amplifier, followed by a narrow bandwidth resonant filter for noise rejection. The overall single pixel responsivity resulted 3590 V root mean square/(W) over bar at 5.8 mu m, and modulation frequency of 85 Hz. The beam spot centroid of a square-wave modulated laser diode emitting 85 mu (W) over bar was determined using an algorithm evaluating the difference signals between diagonal elements along vertical and horizontal scanning directions. An uncertainty in the centroid position of 6 mu m, in both directions, was obtained, mainly limited by the digitizing resolution of the 12-bit acquisition system. (C) 1999 American Institute of Physics. [S0034-6748(99)00502-X].

Journal/Review: REVIEW OF SCIENTIFIC INSTRUMENTS

Volume: 70 (2)      Pages from: 1341  to: 1348

KeyWords: Algorithms; Laser beams; Light emission; Light modulation; Optical filters; Optical sensors; Position measurement; Pyroelectricity; Scanning; Semiconductor lasers; Spurious signal noise, Position sensor; Pyroelectric radiation sensor; Resonant filter; Transimpedance amplifier; Infrared detectors
DOI: 10.1063/1.1149594

ImpactFactor: 1.293
Citations: 8
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