CLEO®/Highly Focused Photonic Nanojet by Molded High Curvature Fiber Micro-Lenses

Achieving highly focused beams out of optical fibers is still very challenging in many applications such as coupling in photonic integrated circuits [1], sensing at nanoscale, sub-diffraction laser processing, and nanoparticle manipulation using optical tweezers. For these applications, the fiber core diameter is generally at least one order of magnitude larger than that of the required spot size. This will cause power losses, low resolution or the requirement to add an external microlens. A fiber micro-lens preserves ideally the compactness of the optical system. However, despite the existence of numerous micro-lens fabrication techniques, it remains difficult to achieve high curvature micro-lenses capable of focusing even beyond the diffraction limit. Such a micro-lens may have both the basis size and the radius close in their dimensions to the fiber core diameter. Our research team propose a new, reproducible, fast and simple to implement fabrication method, capable to tackle the above-mentioned challenges [2].