• Kelkar, H.; Wang, D.; Martín-Cano, D.; Hoffmann, B.; Christiansen, S.; Götzinger, S.; Sandoghar, V.: Sensing Nanoparticles with a Cantilever-Based Scannable Optical Cavity of Low Finesse and Sub-λ3 Volume. Physical Review Applied 4 (2015), p. 054010/1-11

10.1103/PhysRevApplied.4.054010
Open Access Version (externer Anbieter)

Abstract:
We report on the realization of an open plane-concave Fabry-Perot resonator with a mode volume below λ3 at optical frequencies. We discuss some of the less-common features of this microcavity regime and show that the ultrasmall mode volume allows us to detect cavity resonance shifts induced by single nanoparticles even at quality factors as low as 100. Being based on low-reflectivity micromirrors fabricated on a silicon cantilever, our experimental arrangement provides broadband operation, tunability of the cavity resonance, and lateral scanning. These features are interesting for a range of applications including biochemical sensing, modification of photophysics, and optomechanical studies.