Scanning Resonant Nano-Antenna High Resolution Imaging and Emission Control of hBN Defect Photon Emission

Abstract

Single atomic defects in hexagonal boron nitride (hBN) are particularly interesting due to their stability of emission and absence of blinking and bleaching, at ambient conditions [1]. Furthermore, they show exceptional robustness of emission, even at high temperatures of operation [2]. Therefore, hBN defects have emerged as promising candidates for novel robust single photon sources [1]. Several attempts have been done to induce hBN defects in a controlled manner [3,4]. Because of their ease of accessibility and, due to the nanometer scale thickness of the hBN flakes, these defects are attractive to couple to plasmonic structures in order to increase their photon emission [5,6]. However efficient coupling requires a high precision of positioning (<20 nm) and so far the methods adopted lack this level of control, both in assembling and imaging. Also, they present static configurations of coupled emitter-particles and no strategy is adopted in order to discern between the photons emitted by the hBN defects and the luminescence of the metallic particles. Here we present first systematic and simultaneous coupling and imaging of hBN emission centers with resonant optical antennas, with nanometer control and optical resolution of 45 nm (fig. a). We show the capability of nano-antennas to manipulate hBN defects by depleting their emission 30–70% (fig. a,-b). Our setup is a near-field microscope working in scattering configuration, where we fabricate a single dipolar nano-antenna as a near-field probe that we can independently scan over hBN defects controlling the coupling and the fluorescence emission with nanometer resolution [7]. We employ a photon time-gating technique in order to discriminate the light emitted by the metallic antenna by the one radiated by the hBN emitters (fig. b). Finally, we report on a lifetime shortening of 2x, due to coupling emitter—antenna (fig. c,-d).