Advancements on galvanometer scanners for high-end applications

Abstract

Galvanometer-based scanners (GSs) are the most utilized devices for lateral scanning. Their applications range from commercial and industrial to biomedical imaging. They are used mostly for 2-D scanning (with typically two GSs), but also for 1-D or 3-D scanning (the latter by example with GSs in combination with Risley prisms). This paper presents an overview of our contributions in the field of GSs with regard to the requirements of their most challenging applications. Specifically, we studied the optimal scanning functions - to produce the maximum possible duty cycleη, and we found that, contrary to what has been stated in the literature, the scanning function that provides the highest η is not linear plus sinusoidal, but linear plus parabolic. The most common GS input signals (i.e., sawtooth, triangular, and sinusoidal) were investigated experimentally to determine the scanning regimes that produce the minimum image artifacts, for example in Optical Coherence Tomography (OCT). The triangular signal was thus shown to be the best from this point of view, and several rules-of-thumb were extracted to make the best of GSs in OCT. We also discuss aspects of the command functions of GSs that are necessary to achieve a trade-off between a performance criteria related to the duty cycle and voltage regimes of the device. We finally review aspects of the control solutions of GSs we investigated, to obtain the highest possible precision or the fastest possible response of the scanner.