Beschreibung:
<jats:p>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 4×4 mm2 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 /W̄ at 5.8 μm, and modulation frequency of 85 Hz. The beam spot centroid of a square-wave modulated laser diode emitting 85 μW̄ 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 μm, in both directions, was obtained, mainly limited by the digitizing resolution of the 12-bit acquisition system.</jats:p>