ITEE Innovation Expo 2008 : Project Details

Electronically controlled optical system for a ultra-compact laser rangefinder

Laser self-mixing interferometry and its applications are an important area of research in photonics today. Laser self-mixing based sensors and imagers offer many possible advantages over conventional laser interferometry based devices. However there are some problems that arise with laser self-mixing sensors that need to be overcome. One of the most important issues that arise in Laser self-mixing interferometry is the Speckle effect. The speckle effect limits the effectiveness and reliability of laser self-mixing sensors and thus necessitates research into its mitigation. This thesis details research into a control system designed to counteract the influence of the Speckle effect by controlling the position and focus of the laser beam upon the target. The final control system used a dsPIC10F2010 microcontroller with external processing electronics for the controller, and a DVD Pickup type electromechanical lens assembly as the laser beam actuator.