Improvement of laser trapping based microprobe in laser shaded condition

A micro-probe based on laser trapping has been proposed for the probe system of a nano-coordinate measuring machine. This study focused on the "shadow effect," which is the case wherein a partial beam for laser trapping is shaded by the specimen. A radially polarized beam was introduced to improve the shadow effect. As the result of increasing the trapping efficiency by 3.2 times, this high-efficient laser trapping made it possible to extend the measurable range of the vertical surface under the shadow effect.