| Popis: |
We experimentally demonstrate optical trapping of single B. subtilis spores using the enhanced field of a cavity at resonance in a planar silicon photonic crystal. By tracking the suppressed Brownian motion of a spore in three types of optical traps, generated with three type s of cavities (H0, H1 and L3) we derive trap stiffnesses of around 7.6 pN/nm/W and find good agreement with calculated values obtained with 3D FDTD simulations. We envision that planar photonic crystals provide a suitable platform for the manipulation and sensing of bio-particles. Keywords: Photonic crystals, optical trapping, cavity, bacteria, microfluidics, bio-sensing, evanescent, trap stiffness, spores, 1. INTRODUCTION In microbiology and biophysics, optical tweezers have become an important tool for studying and manipulating (bio)particles in an aqueous environment. 1-3 Recently, the combination of photonics and microfluidics, referred to as optofluidics, has gained interest in relation to optical trapping. The reason is that it enables control of the flow of light and of water in a bio-compatible environment, allowing manipulation on the single cell level without the requirement of costly bulk optics and required expertise in operation. On-chip trapping using photonic structures has first been demonstrated using the evanescent field of a waveguide for particle transportation |
