Photonic crystal cavities from hexagonal boron nitride

Abstract

Development of scalable quantum photonic technologies requires on-chip integration of photonic components. Recently, hexagonal boron nitride (hBN) has emerged as a promising platform, following reports of hyperbolic phonon-polaritons and optically stable, ultra-bright quantum emitters. However, exploitation of hBN in scalable, on-chip nanophotonic circuits and cavity quantum electrodynamics (QED) experiments requires robust techniques for the fabrication of high-quality optical resonators. In this letter, we design and engineer suspended photonic crystal cavities from hBN and demonstrate quality (Q) factors in excess of 2000. Subsequently, we show deterministic, iterative tuning of individual cavities by direct-write EBIE without significant degradation of the Q-factor. The demonstration of tunable cavities made from hBN is an unprecedented advance in nanophotonics based on van der Waals materials. Our results and hBN processing methods open up promising avenues for solid-state systems with applications in integrated quantum photonics, polaritonics and cavity QED experiments.

Hexagonal Boron Nitride Phononic Crystal Waveguides

“…A hybrid reactive ion etching (RIE) and electron beam-induced etching (EBIE) technique has been recently developed, but only been implemented to fabricate photonic and optomechanical devices with size limited to tens of micrometers and leaving rough sidewalls. 1 As illustrated in Figure S1a, to circumvent the aforementioned disadvantages, the periodic structures are defined on the commonly used oxidized silicon (290 nm SiO2 on Si) supporting substrates, taking advantage of the well-established patterning and etching techniques with high spatial precision. Then, a suite of specially developed, completely dry exfoliation and transfer techniques are employed.…”

“…The considerable research efforts on exploring the unconventional properties of van der Waals (vdW) layered materials have already led to exciting breakthroughs across a variety of disciplines from fundamental science to device engineering [1,2,3,4,5,6]. Among families of vdW crystals, hexagonal boron nitride (h-BN), having prevailed as gate dielectric and passivation layers in twodimensional (2D) electronics and optoelectronics [7], is emerging as an attractive material platform for nanophotonics and quantum optics [8,9,10].…”

Compact Cavity-Enhanced Single-Photon Generation with Hexagonal Boron Nitride

“…Quantum emitters hosted by hBN have been coupled to plasmonic nanocavities [39]. Hexagonal boron nitride can also be used to fabricate photonic crystal cavities, however, this makes the required spectral matching between optical cavity mode and emitter difficult [40]. Yet, the performance is still not sufficient for use in quantum information experiments.…”

Quantum random number generation using a solid state single photon source

“…Of the latter, point defects that act as single-photon emitters (SPEs) in the van der Waals material hexagonal boron nitride (hBN) have recently gained great attention owing to their exceptional brightness [19], photostability [20] and tunability [21]. The applicability of these emitters for quantum communications has also recently been explored with recent demonstrations of Fourier transform limited line widths [22], and the realization of photonic crystal cavities that allow for Purcell enhancement and applications in cavity quantum electrodynamics [23].…”