Towards ultra-compact optical tweezers without external optics

In this paper, demonstration shows that the optical power level necessary for particle trapping can be achieved by lensed VCSELs. Therefore, the next step will be to adopt lensed VCSELs in integrated optical tweezers. Nowadays, commercial optical tweezers are mainly based on Nd:YAG lasers or edge-emitting laser diodes which are either bulky or need careful external beam correction. Here, the use of vertical-cavity surface-emitting lasers (VCSELs) yields various benefits like micrometer size dimensions, a Gaussian output beam and the fabrication of monolithic two-dimensional laser arrays with which multiple tweezers can be easily realized