A broadband tapered nanocavity for efficient nonclassical light emission

• DOI: 10.1364/oe.24.020904
• Publication Date: 2016-08-31T19:08:09Z
• Authors: Niels Gregersen; Dara P. S. McCutc...; Jesper Mørk; Jean-Michel Gérard; Julien Claudon
• Keywords: [PHYS.PHYS.PHYS-OPTICS] Physics [physics]/Physics [physics]/Optics [physics.optics]; [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics]; [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph]; [SPI.OPTI] Engineering Sciences [physics]/Optics / Photonic; [SPI.NANO] Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics; 0103 physical sciences; [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]; [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic; [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics; 01 natural sciences; 7. Clean energy; [PHYS.COND.CM-MS] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]; [PHYS.QPHY] Physics [physics]/Quantum Physics [quant-ph]

We present the design of a tapered nanocavity, obtained by sandwiching a photonic wire section between a planar gold reflector and a few-period Bragg mirror integrated into the tapered wire. Thanks to its ultrasmall mode volume (0.71 λ3/n3), this hybrid nanocavity largely enhances the spontaneous emission rate of an embedded quantum dot (Purcell factor: 6), while offering a wide operation bandwidth (full-width half-maximum: 20 nm). In addition, the top tapered section shapes the cavity far-field emission into a very directive output beam, with a Gaussian spatial profile. For realistic taper dimensions, a total outcoupling efficiency to a Gaussian beam of 0.8 is predicted. Envisioned applications include bright sources of non-classical states of light, such as widely tunable sources of indistinguishable single photons and polarization-entangled photon pairs.