Hybrid optical antenna with high directivity gain

Alireza Bonakdar, Hooman Mohseni*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


Coupling of a far-field optical mode to electronic states of a quantum absorber or emitter is a crucial process in many applications, including infrared sensors, single molecule spectroscopy, and quantum metrology. In particular, achieving high quantum efficiency for a system with a deep subwavelength quantum absorber/emitter has remained desirable. In this Letter, a hybrid optical antenna based on coupling of a photonic nanojet to a metallo-dielectric antenna is proposed, which allows such efficient coupling. A quantum efficiency of about 50% is predicted for a semiconductor with volume of ̃?3/170. Despite the weak optical absorption coefficient of 2000 cm-1 in the long infrared wavelength of ̃8 μm, very strong far-field coupling has been achieved, as evidenced by an axial directivity gain of 16 dB, which is only 3 dB below of theoretical limit. Unlike the common phased array antenna, this structure does not require coherent sources to achieve a high directivity. The quantum efficiency and directivity gain are more than an order of magnitude higher than existing metallic, dielectric, or metallo-dielectric optical antenna.

Original languageEnglish (US)
Pages (from-to)2726-2728
Number of pages3
JournalOptics Letters
Issue number15
StatePublished - Aug 1 2013

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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