Probing of ultrahigh optical Q-factors of individual liquid microdroplets on superhydrophobic surfaces using tapered optical fiber waveguides

摘要: We report measurements of ultrahigh quality factors (Q-factors) the optical whispering-gallery modes excited via a tapered optical-fiber waveguide in single glycerol–water microdroplets standing on superhydrophobic surface air. Owing to high contact angle mixture (>155°), with geometry truncated sphere minimally distorted by gravity and line pinning effects could be generated. Q-factors up 2.3×106 were observed for such droplets radii 100–200  μm exposed ambient atmosphere closed chamber controlled relative humidity. Placement constant humidity environment permitted prolonged characterization individual microdroplets. found that air stable over more than 1 h their measured values limited mostly thermally induced droplet shape fluctuations.