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L. D. Negro et al.
tice results in a deterministic quasi-periodic sub-lattice of localized plasmon modes
which follow a Fibonacci sequence. In addition, stronger field enhancement was
experimentally observed in Fibonacci structures compared to periodic arrays [130],
demonstrating that quasiperiodic gold nanoparticle arrays can have a significant
impact for the design and fabrication of novel nanoplasmonic devices. The potential
of plasmonic DANS for the engineering of light emitting devices based on the silicon
technology has been recently demonstrated by studying quasi-periodic Fibonacci Au
nanoparticle arrays of varying interparticle separations fabricated on light emitting
Erbium-doped silicon nitride films (Er:SiN x ) by electron beam lithography [131].
A 3.6 times enhancement of the photoluminescence (PL) intensity accompanied
by a reduction of the Er 3+ emission lifetime at 1.54 μm (see Fig. 9.19) has been
observed and explained by the coupling with the near-infrared structural resonances
of the Fibonacci structure. photonic–plasmonic hybrid modes were identified in
a comparative transmission experiment between periodic plasmonic gratings and
Fibonacci quasi-periodic structures by the spectral positions of their transmission
minima, for a large range of fabricated structures.
The scaling behavior of the emission enhancement in Fibonacci and periodic
gratings was discussed in relation to the modifications of the photonic LDOS at
the Er emission wavelength [131]. The strongly reduced frequency sensitivity of
the photonic–plasmonic scattering resonances in Fibonacci arrays prevented their
detuning from the Er emission wavelength. As a result, when decreasing the interparticle separation in the Fibonacci arrays, their emission intensity was found to
increase along with their emission rate, while an opposite behavior, indicative of
non-radiative losses, was observed in periodic gratings. The coupling of light emission to the distinctive scattering resonances of photonic–plasmonic coupled aperiodic arrays makes these systems particularly attractive for radiative rate engineering
applications where light extraction/enhancement is required over broad frequency
spectra.
The distinctive features of circular light scattering in plasmonic Vogel’s spirals,
introduced in Sect. 9.2.4, also provides an alternative approach for broadband light
emission enhancement in active thin films coupled to deterministic aperiodic structures. Our group has recently exploited planar light scattering for light emission
enhancement [66, 71] and demonstrated the role of the inhomogeneous distribution
of local spatial frequencies on the emission patter of Vogel’s spirals [69]. We prepared a dye polymer solution by dissolving common laser dye molecules of DCM
(Exciton Inc.), in toluene.
The dilute solution was then mixed with Polymethylmethacrylate (PMMA), spun
onto samples and cured, resulting in 100 nm thick films of laser dye doped PMMA.
This particular laser dye has maximum absorption at 480 nm and an emission peak
at 640 nm, which overlaps the scattering resonances of the investigated γ 2 -spiral,
leading to broadband emission enhancement, shown in Fig. 9.20b. Moreover, we
demonstrate the ability to dramatically modify the angular emission of the sample
by imaging the fluorescence in transmission under for different excitation conditions.
In particular, the sample was pumped by positioning the laser spot at different locations onto the doped PMMA substrate at normal incidence (focused through a 10×
L. D. Negro et al.
tice results in a deterministic quasi-periodic sub-lattice of localized plasmon modes
which follow a Fibonacci sequence. In addition, stronger field enhancement was
experimentally observed in Fibonacci structures compared to periodic arrays [130],
demonstrating that quasiperiodic gold nanoparticle arrays can have a significant
impact for the design and fabrication of novel nanoplasmonic devices. The potential
of plasmonic DANS for the engineering of light emitting devices based on the silicon
technology has been recently demonstrated by studying quasi-periodic Fibonacci Au
nanoparticle arrays of varying interparticle separations fabricated on light emitting
Erbium-doped silicon nitride films (Er:SiN x ) by electron beam lithography [131].
A 3.6 times enhancement of the photoluminescence (PL) intensity accompanied
by a reduction of the Er 3+ emission lifetime at 1.54 μm (see Fig. 9.19) has been
observed and explained by the coupling with the near-infrared structural resonances
of the Fibonacci structure. photonic–plasmonic hybrid modes were identified in
a comparative transmission experiment between periodic plasmonic gratings and
Fibonacci quasi-periodic structures by the spectral positions of their transmission
minima, for a large range of fabricated structures.
The scaling behavior of the emission enhancement in Fibonacci and periodic
gratings was discussed in relation to the modifications of the photonic LDOS at
the Er emission wavelength [131]. The strongly reduced frequency sensitivity of
the photonic–plasmonic scattering resonances in Fibonacci arrays prevented their
detuning from the Er emission wavelength. As a result, when decreasing the interparticle separation in the Fibonacci arrays, their emission intensity was found to
increase along with their emission rate, while an opposite behavior, indicative of
non-radiative losses, was observed in periodic gratings. The coupling of light emission to the distinctive scattering resonances of photonic–plasmonic coupled aperiodic arrays makes these systems particularly attractive for radiative rate engineering
applications where light extraction/enhancement is required over broad frequency
spectra.
The distinctive features of circular light scattering in plasmonic Vogel’s spirals,
introduced in Sect. 9.2.4, also provides an alternative approach for broadband light
emission enhancement in active thin films coupled to deterministic aperiodic structures. Our group has recently exploited planar light scattering for light emission
enhancement [66, 71] and demonstrated the role of the inhomogeneous distribution
of local spatial frequencies on the emission patter of Vogel’s spirals [69]. We prepared a dye polymer solution by dissolving common laser dye molecules of DCM
(Exciton Inc.), in toluene.
The dilute solution was then mixed with Polymethylmethacrylate (PMMA), spun
onto samples and cured, resulting in 100 nm thick films of laser dye doped PMMA.
This particular laser dye has maximum absorption at 480 nm and an emission peak
at 640 nm, which overlaps the scattering resonances of the investigated γ 2 -spiral,
leading to broadband emission enhancement, shown in Fig. 9.20b. Moreover, we
demonstrate the ability to dramatically modify the angular emission of the sample
by imaging the fluorescence in transmission under for different excitation conditions.
In particular, the sample was pumped by positioning the laser spot at different locations onto the doped PMMA substrate at normal incidence (focused through a 10×