Solid immersion metalens for directional single molecule emission with high collection efficiency

We present simulations of an efficient high numerical aperture solid immersion metalens concept for fluorescence microscopy. The technique exploits the preferential emission of interfacial dipoles into a high refractive index substrate combined with a metalens and a conventional tube lens for imaging them. We have thus simulated dipole emission and an all-dielectric metasurface on opposite sides of a high refractive index substrate. Our calculations predict dipole collection efficiencies of up to 87 percent. The simulated beam propagation through the imaging system shows excellent performance along the optical axis, with aberrations accumulating with increasing field of view. These aberrations can be controlled by using a metasurface with an optimized non-hyperbolic phase profile. The high collection efficiency of dipole emission suggests this compact solid immersion lens would be effective for fluorescence imaging including single fluorescent centres for quantum optical application.