Photonic crystal cavity-enhanced emission from silicon vacancy centers in polycrystalline diamond achieved without postfabrication fine-tuning

• Published in: Nanoscale Vol. 12; no. 24; pp. 1355 - 1363
• Main Authors: Ondi, Lukáš, Varga, Marian, Fait, Jan, Hruška, Karel, Jurka, Vlastimil, Kromka, Alexander, Ma ák, Jan, Kapusta, Peter, Nováková, Jaroslava
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 25.06.2020
• Subjects: Emission; Holes; Lattice vacancies; Phonons; Photonic crystals; Photonics; Polycrystalline diamond; Polycrystals; Post-processing; Room temperature; Silicon; Spectra; Tolerances; Vacancies
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c9nr10580h

Diamond optical centers have recently emerged as promising single-photon sources for quantum photonics. Particularly, negatively charged silicon vacancy (SiV − ) centers show great promise due to their narrow zero-phonon emission line present also at room temperature. However, due to fabrication tolerances it is challenging to prepare directly photonic structures with optical modes spectrally matching the emission of SiV − centers. To reach the spectral overlap, photonic structures must typically undergo complicated post-processing treatment. In this work, suspended photonic crystal cavities made of polycrystalline diamond are engineered and more than 2.5-fold enhancement of the SiV − center zero-phonon line intensity via coupling to the cavity photonic mode is demonstrated. The intrinsic non-homogeneous thickness of the diamond thin layer within the sample is taken as an advantage that enables reaching the spectral overlap between the emission from SiV − centers and the cavity modes without any post-processing. Even with lower optical quality compared to monocrystalline diamond, the fabricated photonic structures show comparable efficiency for intensity enhancement. Therefore, the results of this work may open up a promising route for the application of polycrystalline diamond in photonics. Photonic crystal cavities made of polycrystalline diamond show more than 2.5-fold enhancement of the SiV centers zero-phonon line intensity via coupling to the cavity photonic mode.