Bidirectional coupling of diamond emitters to optical nanowire - tunable and efficient
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2021-10-21 |
| Journal | Journal of the Optical Society of America B |
| Authors | Satyajit Murmu, Avijit Kumar, Rajan Jha |
| Institutions | Indian Institute of Technology Bhubaneswar |
| Citations | 6 |
Abstract
Section titled āAbstractāNegatively charged nitrogen vacancy ( <mml:math xmlns:mml=āhttp://www.w3.org/1998/Math/MathMLā display=āinlineā> <mml:mrow class=āMJX-TeXAtom-ORDā> <mml:msup> <mml:mrow class=āMJX-TeXAtom-ORDā> <mml:mrow class=āMJX-TeXAtom-ORDā> <mml:mi mathvariant=ānormalā>N</mml:mi> <mml:mi mathvariant=ānormalā>V</mml:mi> </mml:mrow> </mml:mrow> <mml:mo>ā</mml:mo> </mml:msup> </mml:mrow> </mml:math> ) centers in diamond are required to be coupled to optical systems for various applications. A slowly varied tapered waveguide displays a near-unity power transfer from an optical fiber to on-chip photonic devices. This physical situation refers to an adiabatic transition of photons from a highly effective confinement mode to a lower effective confinement mode or vice versa. Here, we report tunable bidirectional coupling with enhanced efficiency in a hybrid structure of elliptically faceted (ELFA) diamond nanowire with <mml:math xmlns:mml=āhttp://www.w3.org/1998/Math/MathMLā display=āinlineā> <mml:mrow class=āMJX-TeXAtom-ORDā> <mml:msup> <mml:mrow class=āMJX-TeXAtom-ORDā> <mml:mrow class=āMJX-TeXAtom-ORDā> <mml:mi mathvariant=ānormalā>N</mml:mi> <mml:mi mathvariant=ānormalā>V</mml:mi> </mml:mrow> </mml:mrow> <mml:mo>ā</mml:mo> </mml:msup> </mml:mrow> </mml:math> centers integrated to optical nanowire. Initiating from diabatic transition to adiabatic transition, corresponding to smaller length to longer wire length, respectively, the coupling efficiency oscillates and asymptotically saturates to a maximum value. Our calculations indicate coupling efficiencies of 85% and 84% for azimuthal and radial dipole configurations for the hybrid structure, respectively. The structure with optimum geometry provides similar coupling efficiency of <mml:math xmlns:mml=āhttp://www.w3.org/1998/Math/MathMLā display=āinlineā> <mml:mrow class=āMJX-TeXAtom-ORDā> <mml:mo>ā¼</mml:mo> </mml:mrow> <mml:mrow class=āMJX-TeXAtom-ORDā> <mml:mrow class=āMJX-TeXAtom-ORDā> <mml:mn>81</mml:mn> </mml:mrow> </mml:mrow> <mml:mi mathvariant=ānormalā>%</mml:mi> </mml:math> for radial and azimuthal dipole configurations. By excitation of one of few dipoles placed strategically at various locations in the cylindrical region of the diamond nanowire will allow one to tune coupling efficiency in the two directions. Tailored size and tunable bidirectional coupling of ELFA diamond nanowire with enhanced efficiency will enable its wide-field applications including multi-scale quantum photonics devices.