title: Full spectral and angular characterization of highly directional emission from nanocrystal quantum dots positioned on circular plasmonic lenses.
abstract: We design a circular plasmonic lens for collimation of light emission from nanocrystal quantum dots at room temperature in the near IR spectral range. We implement a two-dimensional k-space imaging technique to obtain the full spectral-angular response of the surface plasmon resonance modes of the bare plasmonic lens. This method is also used to map the full spectral-angular emission from nanocrystal quantum dots positioned at the center of the circular plasmonic lens. A narrow directional emitting beam with a divergence angle of only ∼4.5° full width at half-maximum is achieved with a spectrally broad bandwidth of 30 nm. The spectrally resolved k-space imaging method allows us to get a direct comparison between the spectral-angular response of the resonant surface plasmon modes of the lens and the emission pattern of the quantum dots. This comparison gives a clear and detailed picture of the direct role of these resonant surface waves in directing the emission. The directional emission effect agrees well with calculations based on the coupled mode method. These results are a step toward fabricating an efficient room-temperature single photon source based on nanocrystal quantum dots.
authors.affiliation: Racah Institute of Physics and ‡The Department of Applied Physics, Selim and Rachel Benin School of Engineering and Computer Science, The Hebrew University of Jerusalem , Jerusalem 91904, Israel.
authors.forename: Moshe G
authors.initials: MG
authors.lastname: Harats
authors.forename: Nitzan
authors.initials: N
authors.lastname: Livneh
authors.forename: Gary
authors.initials: G
authors.lastname: Zaiats
authors.forename: Shira
authors.initials: S
authors.lastname: Yochelis
authors.forename: Yossi
authors.initials: Y
authors.lastname: Paltiel
authors.forename: Efrat
authors.initials: E
authors.lastname: Lifshitz
authors.forename: Ronen
authors.initials: R
authors.lastname: Rapaport
keywords: Plasmonic lens; angular-resolved spectroscopy; directional emission; k-space spectroscopy; nanocrystal quantum dot; surface plasmons