Abstract

A good and efficient control of the focus point of a laser beam is essential in many fields such as laser processing and wielding, and confocal microscopy. The most common way of changing the focus position of a beam is to use lenses, usually in the form of a telescope. However, inertia imposes a limit to the frequency at which one can modulate the position of a mechanical element. Other techniques, based on acousto-optic modulators or tunable acoustic gradient lenses exist [1], but most often require to operate in the pulsed-regime, or possess other drawbacks. We present a novel approach for the defocus of a laser beam based on a Multi-Plane Light Conversion device (MPLC) [2] and a modal approach [3].

© 2017 IEEE