« journal navigation
|
Hybrid wedge plasmon polariton waveguide with good fabrication-error-tolerance for ultra-deep-subwavelength mode confinement |
Optics Express, Vol. 19, Issue 23, pp. 22417-22422 (2011)
http://dx.doi.org/10.1364/OE.19.022417
Acrobat PDF (1043 KB)
Article Navigation
▸ Article Outline
– Abstract
1. Introduction
2. Geometry and modal properties of the proposed hybrid WPP waveguides
3. Conclusions
– References and links
– Abstract
1. Introduction
2. Geometry and modal properties of the proposed hybrid WPP waveguides
3. Conclusions
– References and links
Article Tools
Full Text
Article Info
References
Cited By
Figures
Metrics
Download PDF
Viewing Equations in the
HTML Article
Optimal Viewing Recommendations
Abstract
A novel hybrid plasmonic waveguide consisting of a high-index dielectric nanowire placed above a triangular metal wedge substrate is proposed and analyzed theoretically. The strong coupling between the wedge plasmon polariton and the dielectric nanowire mode results in both the ultra-tight confinement and low propagation loss. Compared to the previous studied hybrid surface plasmon polariton structures without the metal wedge substrate, stronger field enhancement in the low-index gap region as well as improved figure of merit (FOM) could be realized simultaneously. Results of the modal properties considering certain fabrication imperfections show that the proposed structure is also quite tolerant to these errors.
© 2011 OSA
1. Introduction
Surface plasmon polariton (SPP) waveguides leveraging the electromagnetic waves coupled to electron oscillations at the metal/dielectric structures have become a hotly studied area in nanophotonics, due to their prospect of deep-subwavelength light guiding [1]. Many novel structures, such as metal slot waveguides [2–5], channel SPP (CPP) waveguides [6,7] and wedge plasmon polariton (WPP) waveguides [8–11], have been proposed, numerically analyzed and experimentally demonstrated. These waveguides could provide tight confinement of light but suffer pretty high propagation loss, which poses challenges for further device integration. Recently, several hybrid plasmonic waveguides have been considered to achieve sub-wavelength mode confinement with relatively low loss [12–17], which could have great impact on realizing optical interconnects at deep sub-wavelength scales. Instead of guiding the light purely by the SPP along the metal/dielectric interface, dielectric index contrast near the metal surface also play an important role in confining the wave in these hybrid SPP waveguides. Although the overall geometrical sizes of their structures are comparable to those of some dielectric nanophotonic devices, these hybrid waveguides offer unique advantages such as large field enhancement, strong light-matter interaction, and lower crosstalk, which make them appealing building blocks for novel integrated nanophotonic components.. Plasmonic nanolasers [18,19] and various functional passive devices, such as directional couplers [20,21], Y-switches [22] and ring-resonators [21], based on such structures had been intensively studied.
W. L. Barnes, A. Dereux, and T. W. Ebbesen, “Surface plasmon subwavelength optics,” Nature 424(6950), 824–830 (2003). [CrossRef] [PubMed]
G. Veronis and S. H. Fan, “Guided subwavelength plasmonic mode supported by a slot in a thin metal film,” Opt. Lett. 30(24), 3359–3361 (2005). [CrossRef] [PubMed]
J. A. Dionne, L. A. Sweatlock, H. A. Atwater, and A. Polman, “Plasmon slot waveguides: towards chip-scale propagation with subwavelength-scale localization,” Phys. Rev. B 73(3), 035407 (2006). [CrossRef]
S. I. Bozhevolnyi, V. S. Volkov, E. Devaux, J. Y. Laluet, and T. W. Ebbesen, “Channel plasmon subwavelength waveguide components including interferometers and ring resonators,” Nature 440(7083), 508–511 (2006). [CrossRef] [PubMed]
E. Moreno, F. J. Garcia-Vidal, S. G. Rodrigo, L. Martin-Moreno, and S. I. Bozhevolnyi, “Channel plasmon-polaritons: modal shape, dispersion, and losses,” Opt. Lett. 31(23), 3447–3449 (2006). [CrossRef] [PubMed]
D. F. P. Pile, T. Ogawa, D. K. Gramotnev, T. Okamoto, M. Haraguchi, M. Fukui, and S. Matsuo, “Theoretical and experimental investigation of strongly localized plasmons on triangular metal wedges for subwavelength waveguiding,” Appl. Phys. Lett. 87(6), 061106 (2005). [CrossRef]
T. Ogawa, D. F. P. Pile, T. Okamoto, M. Haraguchi, M. Fukui, and D. K. Gramotnev, “Numerical and experimental investigation of wedge tip radius effect on wedge plasmons,” J. Appl. Phys. 104(3), 033102 (2008). [CrossRef]
R. F. Oulton, V. J. Sorger, D. A. Genov, D. F. P. Pile, and X. Zhang, “A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation,” Nat. Photonics 2(8), 496–500 (2008). [CrossRef]
Y. S. Zhao and L. Zhu, “Coaxial hybrid plasmonic nanowire waveguides,” J. Opt. Soc. Am. B 27(6), 1260–1265 (2010). [CrossRef]
R. F. Oulton, V. J. Sorger, T. Zentgraf, R. M. Ma, C. Gladden, L. Dai, G. Bartal, and X. Zhang, “Plasmon lasers at deep subwavelength scale,” Nature 461(7264), 629–632 (2009). [CrossRef] [PubMed]
Y. S. Bian, Z. Zheng, Y. Liu, J. S. Zhu, and T. Zhou, “Coplanar plasmonic nanolasers based on edge-coupled hybrid plasmonic waveguides,” IEEE Photon. Technol. Lett. 23(13), 884–886 (2011). [CrossRef]
H. S. Chu, E. P. Li, P. Bai, and R. Hegde, “Optical performance of single-mode hybrid dielectric-loaded plasmonic waveguide-based components,” Appl. Phys. Lett. 96(22), 221103 (2010). [CrossRef]
X. Y. Zhang, A. Hu, J. Z. Wen, T. Zhang, X. J. Xue, Y. Zhou, and W. W. Duley, “Numerical analysis of deep sub-wavelength integrated plasmonic devices based on semiconductor–insulator–metal strip waveguides,” Opt. Express 18(18), 18945–18959 (2010). [CrossRef] [PubMed]
M. Wu, Z. H. Han, and V. Van, “Conductor-gap-silicon plasmonic waveguides and passive components at subwavelength scale,” Opt. Express 18(11), 11728–11736 (2010). [CrossRef] [PubMed]
X. Y. Zhang, A. Hu, J. Z. Wen, T. Zhang, X. J. Xue, Y. Zhou, and W. W. Duley, “Numerical analysis of deep sub-wavelength integrated plasmonic devices based on semiconductor–insulator–metal strip waveguides,” Opt. Express 18(18), 18945–18959 (2010). [CrossRef] [PubMed]
The hybrid plasmonic waveguides are designed based on plasmonic waveguide structures with additional high refractive index dielectric nanostructures placed very close to the metal surface. The optical signal is guided not only at the metal/dielectric interface but also by the index contrast between the high and low index dielectric structures near the metal surface as well. By tuning the hybridization between the SPP modes and the waveguide modes, the characteristics of the hybrid mode can be shifted from dielectric-like toward SPP-like [12]. So far, the studied hybrid plasmonic waveguides are designed based on the traditional traveling SPP along the flat metal/dielectric surface [12], the long-range SPP (LRSPP) mode of thin metal stripes [14], the dielectric-loaded SPP (DLSPP) mode [16], the plasmonic nanowire mode [17], or the plasmonic edge modes of truncated metal films [15,19]. The properties of the hybrid plasmonic modes are heavily influenced by those of the corresponding SPP modes. For example, the long-range hybrid SPP mode of the symmetric hybrid plasmonic waveguide also could possess ultra-low propagation loss similar to that of the traditional LRSPP waveguides [23]. As significantly improving the transmission loss while maintaining a highly confined mode is the goal for most of the hybrid waveguide designs, the compromise between the mode confinement and loss still exists. Reduced effective mode area is realized when the gap between the high-index structure and the metal surface is shrunk. The hybrid plasmonic waveguide is shown to be able to achieve ultra-deep-subwavelength mode area with a very small gap width in [12]. However, limited by the mode confinement capability of the corresponding SPP modes involved, further downscaling of the hybrid mode area seems difficult as the gap width is already minimized for practical implementations.
R. F. Oulton, V. J. Sorger, D. A. Genov, D. F. P. Pile, and X. Zhang, “A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation,” Nat. Photonics 2(8), 496–500 (2008). [CrossRef]
R. F. Oulton, V. J. Sorger, D. A. Genov, D. F. P. Pile, and X. Zhang, “A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation,” Nat. Photonics 2(8), 496–500 (2008). [CrossRef]
Y. S. Bian, Z. Zheng, X. Zhao, J. S. Zhu, and T. Zhou, “Symmetric hybrid surface plasmon polariton waveguides for 3D photonic integration,” Opt. Express 17(23), 21320–21325 (2009). [CrossRef] [PubMed]
Y. S. Bian, Z. Zheng, Y. Liu, J. S. Zhu, and T. Zhou, “Dielectric-loaded surface plasmon polariton waveguide with a holey ridge for propagation-loss reduction and subwavelength mode confinement,” Opt. Express 18(23), 23756–23762 (2010). [CrossRef] [PubMed]
Y. S. Zhao and L. Zhu, “Coaxial hybrid plasmonic nanowire waveguides,” J. Opt. Soc. Am. B 27(6), 1260–1265 (2010). [CrossRef]
I. Avrutsky, R. Soref, and W. Buchwald, “Sub-wavelength plasmonic modes in a conductor-gap-dielectric system with a nanoscale gap,” Opt. Express 18(1), 348–363 (2010). [CrossRef] [PubMed]
Y. S. Bian, Z. Zheng, Y. Liu, J. S. Zhu, and T. Zhou, “Coplanar plasmonic nanolasers based on edge-coupled hybrid plasmonic waveguides,” IEEE Photon. Technol. Lett. 23(13), 884–886 (2011). [CrossRef]
P. Berini, “Plasmon-polariton waves guided by thin lossy metal films of finite width: bound modes of symmetric structures,” Phys. Rev. B 61(15), 10484–10503 (2000). [CrossRef]
R. F. Oulton, V. J. Sorger, D. A. Genov, D. F. P. Pile, and X. Zhang, “A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation,” Nat. Photonics 2(8), 496–500 (2008). [CrossRef]
To circumvent the above problem and find an alternative approach to reduce the mode area, here we propose a novel hybrid plasmonic waveguide that employs a triangular metal wedge as the substrate. By exploiting the extraordinary confinement property of the wedge plasmon polariton (WPP) [8–11] at the top corner of the wedge and the advantages of the hybrid structures [12], a novel hybrid WPP waveguide is proposed. Simulation reveals that, compared to the previously demonstrated flat metallic substrate based hybrid plasmonic waveguide, the hybrid WPP waveguide could achieve even stronger mode confinement with similar propagation length. Such ultra-deep-subwavelength confinement could enable various applications such as ultra-compact integrated photonic components, manipulation of particles by optical forces [24], and more.
D. F. P. Pile, T. Ogawa, D. K. Gramotnev, T. Okamoto, M. Haraguchi, M. Fukui, and S. Matsuo, “Theoretical and experimental investigation of strongly localized plasmons on triangular metal wedges for subwavelength waveguiding,” Appl. Phys. Lett. 87(6), 061106 (2005). [CrossRef]
T. Ogawa, D. F. P. Pile, T. Okamoto, M. Haraguchi, M. Fukui, and D. K. Gramotnev, “Numerical and experimental investigation of wedge tip radius effect on wedge plasmons,” J. Appl. Phys. 104(3), 033102 (2008). [CrossRef]
R. F. Oulton, V. J. Sorger, D. A. Genov, D. F. P. Pile, and X. Zhang, “A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation,” Nat. Photonics 2(8), 496–500 (2008). [CrossRef]
X. D. Yang, Y. M. Liu, R. F. Oulton, X. B. Yin, and X. A. Zhang, “Optical forces in hybrid plasmonic waveguides,” Nano Lett. 11(2), 321–328 (2011). [CrossRef] [PubMed]
2. Geometry and modal properties of the proposed hybrid WPP waveguides
The schematic of the proposed hybrid WPP waveguide is shown in Fig. 1
, which consists of a high-index dielectric nanowire embedded in a low-index cladding near the metallic wedge substrate. Here we assume the nanowire is placed directly above the wedge with a gap width of h away from the top edge of the wedge. The metal wedge tip has an angle of θ and a curvature radius of r, while the wedge height is hw. The diameter of the nanowire is d. The characteristics of the hybrid WPP waveguides are investigated at λ = 1550nm. The metallic substrate is assumed to be silver (Ag), the high-index dielectric is silicon (Si), and the cladding is silica (SiO2). The permittivities of SiO2, Si and Ag are εc = 2.25, εd = 12.25 and εm = −129 + 3.3i [25], respectively. The modal properties are investigated by means of the finite-element method (FEM) using COMSOLTM. The eigenmode solver is used with the scattering boundary condition. Convergence tests are done to ensure that the numerical boundaries and meshing do not interfere with the solutions.
P. B. Johnson and R. W. Christy, “Optical constants of the noble metals,” Phys. Rev. B 6(12), 4370–4379 (1972). [CrossRef]
We first consider waveguide configurations with nontruncated metal wedges (i.e. hw→∞).To avoid singularities in simulations, the tip of the top corner are rounded with a 10nm curvature [26]. |E(x,y)| distributions of the fundamental plasmonic mode of the hybrid WPP waveguides are shown in Fig. 2
, where the diameter of the nanowire is fixed at 200nm and the distance h is set at 5nm. The metal wedge tip-angle is chosen at 20deg, 60deg, 100deg, 140deg and 180deg, respectively. We note that the extreme case of 180deg corresponds to the hybrid plasmonic waveguide with flat metallic substrate as investigated in [12]. It is shown that for all the above cases, the low-index nanogap between the dielectric nanowire and the metal wedge could effectively confine a large portion of the field due to the slot effect [12,16,27]. A metal wedge with smaller θ would result in stronger field enhancement in the gap region, especially near the wedge tip. At larger θ, the field enhancement is less obvious, and more electric field is distributed along the metal surface, leading to an increased mode area. These phenomena suggest that in order to suppress the mode area and enhance the mode confinement, a metal wedge with a sharper tip is preferred.
M. Yan and M. Qiu, “Guided plasmon polariton at 2D metal corners,” J. Opt. Soc. Am. B 24(9), 2333–2342 (2007). [CrossRef]
R. F. Oulton, V. J. Sorger, D. A. Genov, D. F. P. Pile, and X. Zhang, “A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation,” Nat. Photonics 2(8), 496–500 (2008). [CrossRef]
R. F. Oulton, V. J. Sorger, D. A. Genov, D. F. P. Pile, and X. Zhang, “A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation,” Nat. Photonics 2(8), 496–500 (2008). [CrossRef]
Y. S. Bian, Z. Zheng, Y. Liu, J. S. Zhu, and T. Zhou, “Dielectric-loaded surface plasmon polariton waveguide with a holey ridge for propagation-loss reduction and subwavelength mode confinement,” Opt. Express 18(23), 23756–23762 (2010). [CrossRef] [PubMed]
V. R. Almeida, Q. F. Xu, C. A. Barrios, and M. Lipson, “Guiding and confining light in void nanostructure,” Opt. Lett. 29(11), 1209–1211 (2004). [CrossRef] [PubMed]
Fig. 2 (a)-(e)|E(x,y)| distributions of the fundamental plasmonic mode of hybrid WPP waveguides with different tip-angles (h = 5nm), where the extreme case of θ = 180deg corresponds to the hybrid plasmonic waveguide in [12] (The top tip of the metal wedge are rounded with a curvature of 10nm. Note that the field distributions are normalized so that the surface integrals of the power flow in the cross section are equal); (f) |E(x,y)| distributions along y direction at the center position of the nanowire.
R. F. Oulton, V. J. Sorger, D. A. Genov, D. F. P. Pile, and X. Zhang, “A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation,” Nat. Photonics 2(8), 496–500 (2008). [CrossRef]
The modal effective index (Neff), propagation length (Lp), normalized mode area (Aeff /A0) and figure of merit (FOM) of the SPP mode of our proposed structures with different tip-angles are shown in Fig. 3
as θ varies from 20deg to 180deg. The propagation length is given by Lp = λ/[4πIm(neff)]. A0 is the diffraction-limited mode area and defined as λ2/4. The effective mode area (Aeff) is calculated using, where, to accurately account for the energy in the metal region, the electromagnetic energy density W(r) is defined as [5,28]:where E(r) and H(r) are the electric and magnetic fields, ε(r) is the electric permittivity and μ0 is the vacuum magnetic permeability. FOM is defined as the ratio of Lp to Deff [29], where Deff is the effective mode size defined as the diameter of Aeff.
J. A. Dionne, L. A. Sweatlock, H. A. Atwater, and A. Polman, “Plasmon slot waveguides: towards chip-scale propagation with subwavelength-scale localization,” Phys. Rev. B 73(3), 035407 (2006). [CrossRef]
R. F. Oulton, G. Bartal, D. F. P. Pile, and X. Zhang, “Confinement and propagation characteristics of subwavelength plasmonic modes,” N. J. Phys. 10(10), 105018 (2008). [CrossRef]
R. Buckley and P. Berini, “Figures of merit for 2D surface plasmon waveguides and application to metal stripes,” Opt. Express 15(19), 12174–12182 (2007). [CrossRef] [PubMed]
Fig. 3 Dependence of the modal properties of the fundamental plasmonic mode of the proposed hybrid WPP waveguide on the tip-angle of the metal wedge: (a) the modal effective index (Neff) and the propagation length (Lp); (b) the normalized mode area (Aeff /A0) and figure of merit (FOM). Solid line: h = 2nm; dashed line: h = 5nm; dash-dotted line: h = 10nm.
Figure 3(a) illustrates that the mode effective index decreases monotonically with increased tip-angles, indicating a gradually weakened confinement at larger θ, which is consistent with the trend of increased effective mode area as shown in Fig. 3(b). While the propagation length is shown to increase first before it decreases when the metal wedge shifts towards flat metallic surface, which indicates the existence of an optimized tip angle (~140 deg) with respect to Lp. When θ is around 140 deg, the corresponding hybrid WPP waveguide could achieve longer propagation length with much smaller mode area compared to the previous hybrid plasmonic waveguide [12]. This indicates that ultra-deep subwavelength mode confinement could be simultaneously realized along with relatively low transmission loss based on our proposed structure. Calculations of the figure of merit at various tip-angles show that the overall performance of the proposed hybrid WPP structure could be better than that of the hybrid plasmonic waveguide with a flat metallic substrate in most cases. On the other hand, similar to hybrid plasmonic waveguides [12], Neff decreases while Lp and Aeff increase at larger gap width. The propagation lengths in Fig. 3 are comparable to those of the dielectric-loaded plasmonic waveguides but with much stronger confinement, which could be used to realize various devices such as plasmonic Bragg grating and other wavelength-selective structures, as well as active devices including nanolasers. We also note Lp could be increased to even hundreds of microns by further increasing the gap widths at the expense of weaker field confinement. Our results indicate that between 20 to 40% of the total power resides in the high-index nanowire for the geometrical parameters in Fig. 3, indicating sufficient modal overlap for possible applications like nanolasers [18,19].
R. F. Oulton, V. J. Sorger, D. A. Genov, D. F. P. Pile, and X. Zhang, “A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation,” Nat. Photonics 2(8), 496–500 (2008). [CrossRef]
R. F. Oulton, V. J. Sorger, D. A. Genov, D. F. P. Pile, and X. Zhang, “A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation,” Nat. Photonics 2(8), 496–500 (2008). [CrossRef]
R. F. Oulton, V. J. Sorger, T. Zentgraf, R. M. Ma, C. Gladden, L. Dai, G. Bartal, and X. Zhang, “Plasmon lasers at deep subwavelength scale,” Nature 461(7264), 629–632 (2009). [CrossRef] [PubMed]
Y. S. Bian, Z. Zheng, Y. Liu, J. S. Zhu, and T. Zhou, “Coplanar plasmonic nanolasers based on edge-coupled hybrid plasmonic waveguides,” IEEE Photon. Technol. Lett. 23(13), 884–886 (2011). [CrossRef]
Then we consider more realistic waveguide configurations with metal wedges truncated at a certain height. The dependence of modal properties on the metal wedge height at different tip-angles are shown in Fig. 4 (a)-(c)
. Unlike the traditional WPP waveguides [9], there is no critical height below which the mode is no longer guided for our proposed waveguides. At relatively large hw (e.g. >300nm), the modal properties of the hybrid WPP waveguides quickly reach those under infinitely large hw as shown in Fig. 3. Thus, the waveguide’s characteristics are robust against the variation of the metal wedge height when the wedge is not too shallow. On the other hand, when hw is very small, the coupling between the dielectric nanowire and the bottom flat metal substrate becomes more obvious. This results in more complex mode properties, such as the non-monotonical changes of the curves shown in Fig. 4. The mode eventually approaches that from a flat metal surface [12] as the metal wedge gradually diminishes.
E. Moreno, S. G. Rodrigo, S. I. Bozhevolnyi, L. Martín-Moreno, and F. J. García-Vidal, “Guiding and focusing of electromagnetic fields with wedge plasmon polaritons,” Phys. Rev. Lett. 100(2), 023901 (2008). [CrossRef] [PubMed]
R. F. Oulton, V. J. Sorger, D. A. Genov, D. F. P. Pile, and X. Zhang, “A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation,” Nat. Photonics 2(8), 496–500 (2008). [CrossRef]
Fig. 4 Dependence of the modal properties of the fundamental plasmonic mode of the proposed hybrid WPP waveguide on the wedge heights: (a) the modal effective index (Neff) and the propagation length (Lp); (b) the normalized mode area (Aeff /A0) and figure of merit (FOM).Dashed-lines correspond to the hybrid WPP waveguides with infinite metal wedge heights.
To fabricate such a waveguide, the focused-ion beam (FIB) technique could be used to form the metal wedge with high accuracy and the Si nanowire can then be placed after depositing a thin SiO2 layer on the wedge. Another approach might be using a reverse step by positioning the Si nanowire on a SiO2 substrate and then covering the nanowire with a SiO2 cladding first. The metal will later be deposited after milling a V-shape groove in the upper silica layer, similar as the fabrication process for the WPP waveguide in [10]. Considering the practical fabrication issues for the proposed hybrid WPP waveguide, while the size of the dielectric nanowire and the gap width h could be controlled with high precision [18], the curvature radius of the metal tip may vary [8–11] and the accurate alignment between the metal wedge and the nanowire is also difficult. Therefore, we further investigate in detail the impact of the above common fabrication imperfections on the modal properties. In Fig. 5
, the effects of the tip radius and the misalignment between the wedge and the wire on the propagation length and effective mode area are shown at different tip angles. It is noted that for metal wedges with larger tip-angles (e.g.>60deg), the variation of r causes little changes in Lp and Aeff. When r increases from 10nm to 20nm, the changes in Lp and Aeff are only ~2% and ~5%, respectively. However, when θ is small (e.g. 20deg), the difference of the modal properties at various r becomes more obvious, especially when the radius is very small (e.g.<5nm). Figure 5(b) shows that, for all the considered tip-angles, a ± 10nm misalignment in the horizontal direction only result in a less than 3% fluctuation for Lp and a no more than 5% variation for Aeff. The modifications in the mode profile are also negligible. The above results clearly indicate that the proposed hybrid WPP waveguide is quite tolerant to fabrication errors, especially at larger tip-angles, which is beneficial for its implementations.
A. Boltasseva, V. S. Volkov, R. B. Nielsen, E. Moreno, S. G. Rodrigo, and S. I. Bozhevolnyi, “Triangular metal wedges for subwavelength plasmon-polariton guiding at telecom wavelengths,” Opt. Express 16(8), 5252–5260 (2008). [CrossRef] [PubMed]
R. F. Oulton, V. J. Sorger, T. Zentgraf, R. M. Ma, C. Gladden, L. Dai, G. Bartal, and X. Zhang, “Plasmon lasers at deep subwavelength scale,” Nature 461(7264), 629–632 (2009). [CrossRef] [PubMed]
D. F. P. Pile, T. Ogawa, D. K. Gramotnev, T. Okamoto, M. Haraguchi, M. Fukui, and S. Matsuo, “Theoretical and experimental investigation of strongly localized plasmons on triangular metal wedges for subwavelength waveguiding,” Appl. Phys. Lett. 87(6), 061106 (2005). [CrossRef]
T. Ogawa, D. F. P. Pile, T. Okamoto, M. Haraguchi, M. Fukui, and D. K. Gramotnev, “Numerical and experimental investigation of wedge tip radius effect on wedge plasmons,” J. Appl. Phys. 104(3), 033102 (2008). [CrossRef]
Fig. 5 Dependence of the modal properties on (a) the metal tip curvature radius r and (b) the misalignment δx (r = 10nm). Solid line: Lp ; dashed line: Aeff /A0 , when h = 5nm.
To couple to the proposed hybrid plasmonic waveguide with a deep-subwavelength mode size, coupling schemes for the traditional wedge plasmon polariton modes by means of the continuously geometrically deformed metal surface [9] could be adopted, while a reversed configuration could be used to convert the hybrid WPP mode to the conventional hybrid plasmonic mode (i.e. the hybrid mode on the flat metal surface as in [12]).
E. Moreno, S. G. Rodrigo, S. I. Bozhevolnyi, L. Martín-Moreno, and F. J. García-Vidal, “Guiding and focusing of electromagnetic fields with wedge plasmon polaritons,” Phys. Rev. Lett. 100(2), 023901 (2008). [CrossRef] [PubMed]
R. F. Oulton, V. J. Sorger, D. A. Genov, D. F. P. Pile, and X. Zhang, “A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation,” Nat. Photonics 2(8), 496–500 (2008). [CrossRef]
3. Conclusions
In this paper, we have proposed and studied a novel hybrid plasmonic structure based on the wedge plasmon polariton waveguide. The combination of the unique properties of WPP and the advantages associated with the hybrid plasmonic structures provide us a new avenue to further improve some of the key characteristics of the waveguide. By optimizing the waveguide geometry, ultra-deep-subwavelength mode confinement could be achieved while maintaining relatively long propagation distance. Simulation results reveal the structure is also quite tolerant to fabrication errors.
Acknowledgments
This work was supported by 973 Program (2009CB930701), NSFC (60921001/61077064) and PCSIRT, SEM, and the Innovation Foundation of BUAA for PhD Graduates.
References and links
W. L. Barnes, A. Dereux, and T. W. Ebbesen, “Surface plasmon subwavelength optics,” Nature 424(6950), 824–830 (2003). [CrossRef] [PubMed] | |
G. Veronis and S. H. Fan, “Guided subwavelength plasmonic mode supported by a slot in a thin metal film,” Opt. Lett. 30(24), 3359–3361 (2005). [CrossRef] [PubMed] | |
D. F. P. Pile, T. Ogawa, D. K. Gramotnev, Y. Matsuzaki, K. C. Vernon, K. Yamaguchi, T. Okamoto, M. Haraguchi, and M. Fukui, “Two-dimensionally localized modes of a nanoscale gap plasmon waveguide,” Appl. Phys. Lett. 87(26), 261114 (2005). [CrossRef] | |
L. Liu, Z. Han, and S. He, “Novel surface plasmon waveguide for high integration,” Opt. Express 13(17), 6645–6650 (2005). [CrossRef] [PubMed] | |
J. A. Dionne, L. A. Sweatlock, H. A. Atwater, and A. Polman, “Plasmon slot waveguides: towards chip-scale propagation with subwavelength-scale localization,” Phys. Rev. B 73(3), 035407 (2006). [CrossRef] | |
S. I. Bozhevolnyi, V. S. Volkov, E. Devaux, J. Y. Laluet, and T. W. Ebbesen, “Channel plasmon subwavelength waveguide components including interferometers and ring resonators,” Nature 440(7083), 508–511 (2006). [CrossRef] [PubMed] | |
E. Moreno, F. J. Garcia-Vidal, S. G. Rodrigo, L. Martin-Moreno, and S. I. Bozhevolnyi, “Channel plasmon-polaritons: modal shape, dispersion, and losses,” Opt. Lett. 31(23), 3447–3449 (2006). [CrossRef] [PubMed] | |
D. F. P. Pile, T. Ogawa, D. K. Gramotnev, T. Okamoto, M. Haraguchi, M. Fukui, and S. Matsuo, “Theoretical and experimental investigation of strongly localized plasmons on triangular metal wedges for subwavelength waveguiding,” Appl. Phys. Lett. 87(6), 061106 (2005). [CrossRef] | |
E. Moreno, S. G. Rodrigo, S. I. Bozhevolnyi, L. Martín-Moreno, and F. J. García-Vidal, “Guiding and focusing of electromagnetic fields with wedge plasmon polaritons,” Phys. Rev. Lett. 100(2), 023901 (2008). [CrossRef] [PubMed] | |
A. Boltasseva, V. S. Volkov, R. B. Nielsen, E. Moreno, S. G. Rodrigo, and S. I. Bozhevolnyi, “Triangular metal wedges for subwavelength plasmon-polariton guiding at telecom wavelengths,” Opt. Express 16(8), 5252–5260 (2008). [CrossRef] [PubMed] | |
T. Ogawa, D. F. P. Pile, T. Okamoto, M. Haraguchi, M. Fukui, and D. K. Gramotnev, “Numerical and experimental investigation of wedge tip radius effect on wedge plasmons,” J. Appl. Phys. 104(3), 033102 (2008). [CrossRef] | |
R. F. Oulton, V. J. Sorger, D. A. Genov, D. F. P. Pile, and X. Zhang, “A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation,” Nat. Photonics 2(8), 496–500 (2008). [CrossRef] | |
D. X. Dai and S. L. He, “A silicon-based hybrid plasmonic waveguide with a metal cap for a nano-scale light confinement,” Opt. Express 17(19), 16646–16653 (2009). [CrossRef] [PubMed] | |
Y. S. Bian, Z. Zheng, X. Zhao, J. S. Zhu, and T. Zhou, “Symmetric hybrid surface plasmon polariton waveguides for 3D photonic integration,” Opt. Express 17(23), 21320–21325 (2009). [CrossRef] [PubMed] | |
I. Avrutsky, R. Soref, and W. Buchwald, “Sub-wavelength plasmonic modes in a conductor-gap-dielectric system with a nanoscale gap,” Opt. Express 18(1), 348–363 (2010). [CrossRef] [PubMed] | |
Y. S. Bian, Z. Zheng, Y. Liu, J. S. Zhu, and T. Zhou, “Dielectric-loaded surface plasmon polariton waveguide with a holey ridge for propagation-loss reduction and subwavelength mode confinement,” Opt. Express 18(23), 23756–23762 (2010). [CrossRef] [PubMed] | |
Y. S. Zhao and L. Zhu, “Coaxial hybrid plasmonic nanowire waveguides,” J. Opt. Soc. Am. B 27(6), 1260–1265 (2010). [CrossRef] | |
R. F. Oulton, V. J. Sorger, T. Zentgraf, R. M. Ma, C. Gladden, L. Dai, G. Bartal, and X. Zhang, “Plasmon lasers at deep subwavelength scale,” Nature 461(7264), 629–632 (2009). [CrossRef] [PubMed] | |
Y. S. Bian, Z. Zheng, Y. Liu, J. S. Zhu, and T. Zhou, “Coplanar plasmonic nanolasers based on edge-coupled hybrid plasmonic waveguides,” IEEE Photon. Technol. Lett. 23(13), 884–886 (2011). [CrossRef] | |
H. S. Chu, E. P. Li, P. Bai, and R. Hegde, “Optical performance of single-mode hybrid dielectric-loaded plasmonic waveguide-based components,” Appl. Phys. Lett. 96(22), 221103 (2010). [CrossRef] | |
X. Y. Zhang, A. Hu, J. Z. Wen, T. Zhang, X. J. Xue, Y. Zhou, and W. W. Duley, “Numerical analysis of deep sub-wavelength integrated plasmonic devices based on semiconductor–insulator–metal strip waveguides,” Opt. Express 18(18), 18945–18959 (2010). [CrossRef] [PubMed] | |
M. Wu, Z. H. Han, and V. Van, “Conductor-gap-silicon plasmonic waveguides and passive components at subwavelength scale,” Opt. Express 18(11), 11728–11736 (2010). [CrossRef] [PubMed] | |
P. Berini, “Plasmon-polariton waves guided by thin lossy metal films of finite width: bound modes of symmetric structures,” Phys. Rev. B 61(15), 10484–10503 (2000). [CrossRef] | |
X. D. Yang, Y. M. Liu, R. F. Oulton, X. B. Yin, and X. A. Zhang, “Optical forces in hybrid plasmonic waveguides,” Nano Lett. 11(2), 321–328 (2011). [CrossRef] [PubMed] | |
P. B. Johnson and R. W. Christy, “Optical constants of the noble metals,” Phys. Rev. B 6(12), 4370–4379 (1972). [CrossRef] | |
M. Yan and M. Qiu, “Guided plasmon polariton at 2D metal corners,” J. Opt. Soc. Am. B 24(9), 2333–2342 (2007). [CrossRef] | |
V. R. Almeida, Q. F. Xu, C. A. Barrios, and M. Lipson, “Guiding and confining light in void nanostructure,” Opt. Lett. 29(11), 1209–1211 (2004). [CrossRef] [PubMed] | |
R. F. Oulton, G. Bartal, D. F. P. Pile, and X. Zhang, “Confinement and propagation characteristics of subwavelength plasmonic modes,” N. J. Phys. 10(10), 105018 (2008). [CrossRef] | |
R. Buckley and P. Berini, “Figures of merit for 2D surface plasmon waveguides and application to metal stripes,” Opt. Express 15(19), 12174–12182 (2007). [CrossRef] [PubMed] |
OCIS Codes
(130.2790) Integrated optics : Guided waves
(240.6680) Optics at surfaces : Surface plasmons
(250.5300) Optoelectronics : Photonic integrated circuits
ToC Category:
Optics at Surfaces
History
Original Manuscript: April 22, 2011
Revised Manuscript: June 11, 2011
Manuscript Accepted: June 14, 2011
Published: October 24, 2011
Citation
Yusheng Bian, Zheng Zheng, Ya Liu, Jiansheng Liu, Jinsong Zhu, and Tao Zhou, "Hybrid wedge plasmon polariton waveguide with good fabrication-error-tolerance for ultra-deep-subwavelength mode confinement," Opt. Express 19, 22417-22422 (2011)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-23-22417
Sort: Year | Journal | Reset
References
- W. L. Barnes, A. Dereux, and T. W. Ebbesen, “Surface plasmon subwavelength optics,” Nature424(6950), 824–830 (2003). [CrossRef] [PubMed]
- G. Veronis and S. H. Fan, “Guided subwavelength plasmonic mode supported by a slot in a thin metal film,” Opt. Lett.30(24), 3359–3361 (2005). [CrossRef] [PubMed]
- D. F. P. Pile, T. Ogawa, D. K. Gramotnev, Y. Matsuzaki, K. C. Vernon, K. Yamaguchi, T. Okamoto, M. Haraguchi, and M. Fukui, “Two-dimensionally localized modes of a nanoscale gap plasmon waveguide,” Appl. Phys. Lett.87(26), 261114 (2005). [CrossRef]
- L. Liu, Z. Han, and S. He, “Novel surface plasmon waveguide for high integration,” Opt. Express13(17), 6645–6650 (2005). [CrossRef] [PubMed]
- J. A. Dionne, L. A. Sweatlock, H. A. Atwater, and A. Polman, “Plasmon slot waveguides: towards chip-scale propagation with subwavelength-scale localization,” Phys. Rev. B73(3), 035407 (2006). [CrossRef]
- S. I. Bozhevolnyi, V. S. Volkov, E. Devaux, J. Y. Laluet, and T. W. Ebbesen, “Channel plasmon subwavelength waveguide components including interferometers and ring resonators,” Nature440(7083), 508–511 (2006). [CrossRef] [PubMed]
- E. Moreno, F. J. Garcia-Vidal, S. G. Rodrigo, L. Martin-Moreno, and S. I. Bozhevolnyi, “Channel plasmon-polaritons: modal shape, dispersion, and losses,” Opt. Lett.31(23), 3447–3449 (2006). [CrossRef] [PubMed]
- D. F. P. Pile, T. Ogawa, D. K. Gramotnev, T. Okamoto, M. Haraguchi, M. Fukui, and S. Matsuo, “Theoretical and experimental investigation of strongly localized plasmons on triangular metal wedges for subwavelength waveguiding,” Appl. Phys. Lett.87(6), 061106 (2005). [CrossRef]
- E. Moreno, S. G. Rodrigo, S. I. Bozhevolnyi, L. Martín-Moreno, and F. J. García-Vidal, “Guiding and focusing of electromagnetic fields with wedge plasmon polaritons,” Phys. Rev. Lett.100(2), 023901 (2008). [CrossRef] [PubMed]
- A. Boltasseva, V. S. Volkov, R. B. Nielsen, E. Moreno, S. G. Rodrigo, and S. I. Bozhevolnyi, “Triangular metal wedges for subwavelength plasmon-polariton guiding at telecom wavelengths,” Opt. Express16(8), 5252–5260 (2008). [CrossRef] [PubMed]
- T. Ogawa, D. F. P. Pile, T. Okamoto, M. Haraguchi, M. Fukui, and D. K. Gramotnev, “Numerical and experimental investigation of wedge tip radius effect on wedge plasmons,” J. Appl. Phys.104(3), 033102 (2008). [CrossRef]
- R. F. Oulton, V. J. Sorger, D. A. Genov, D. F. P. Pile, and X. Zhang, “A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation,” Nat. Photonics2(8), 496–500 (2008). [CrossRef]
- D. X. Dai and S. L. He, “A silicon-based hybrid plasmonic waveguide with a metal cap for a nano-scale light confinement,” Opt. Express17(19), 16646–16653 (2009). [CrossRef] [PubMed]
- Y. S. Bian, Z. Zheng, X. Zhao, J. S. Zhu, and T. Zhou, “Symmetric hybrid surface plasmon polariton waveguides for 3D photonic integration,” Opt. Express17(23), 21320–21325 (2009). [CrossRef] [PubMed]
- I. Avrutsky, R. Soref, and W. Buchwald, “Sub-wavelength plasmonic modes in a conductor-gap-dielectric system with a nanoscale gap,” Opt. Express18(1), 348–363 (2010). [CrossRef] [PubMed]
- Y. S. Bian, Z. Zheng, Y. Liu, J. S. Zhu, and T. Zhou, “Dielectric-loaded surface plasmon polariton waveguide with a holey ridge for propagation-loss reduction and subwavelength mode confinement,” Opt. Express18(23), 23756–23762 (2010). [CrossRef] [PubMed]
- Y. S. Zhao and L. Zhu, “Coaxial hybrid plasmonic nanowire waveguides,” J. Opt. Soc. Am. B27(6), 1260–1265 (2010). [CrossRef]
- R. F. Oulton, V. J. Sorger, T. Zentgraf, R. M. Ma, C. Gladden, L. Dai, G. Bartal, and X. Zhang, “Plasmon lasers at deep subwavelength scale,” Nature461(7264), 629–632 (2009). [CrossRef] [PubMed]
- Y. S. Bian, Z. Zheng, Y. Liu, J. S. Zhu, and T. Zhou, “Coplanar plasmonic nanolasers based on edge-coupled hybrid plasmonic waveguides,” IEEE Photon. Technol. Lett.23(13), 884–886 (2011). [CrossRef]
- H. S. Chu, E. P. Li, P. Bai, and R. Hegde, “Optical performance of single-mode hybrid dielectric-loaded plasmonic waveguide-based components,” Appl. Phys. Lett.96(22), 221103 (2010). [CrossRef]
- X. Y. Zhang, A. Hu, J. Z. Wen, T. Zhang, X. J. Xue, Y. Zhou, and W. W. Duley, “Numerical analysis of deep sub-wavelength integrated plasmonic devices based on semiconductor–insulator–metal strip waveguides,” Opt. Express18(18), 18945–18959 (2010). [CrossRef] [PubMed]
- M. Wu, Z. H. Han, and V. Van, “Conductor-gap-silicon plasmonic waveguides and passive components at subwavelength scale,” Opt. Express18(11), 11728–11736 (2010). [CrossRef] [PubMed]
- P. Berini, “Plasmon-polariton waves guided by thin lossy metal films of finite width: bound modes of symmetric structures,” Phys. Rev. B61(15), 10484–10503 (2000). [CrossRef]
- X. D. Yang, Y. M. Liu, R. F. Oulton, X. B. Yin, and X. A. Zhang, “Optical forces in hybrid plasmonic waveguides,” Nano Lett.11(2), 321–328 (2011). [CrossRef] [PubMed]
- P. B. Johnson and R. W. Christy, “Optical constants of the noble metals,” Phys. Rev. B6(12), 4370–4379 (1972). [CrossRef]
- M. Yan and M. Qiu, “Guided plasmon polariton at 2D metal corners,” J. Opt. Soc. Am. B24(9), 2333–2342 (2007). [CrossRef]
- V. R. Almeida, Q. F. Xu, C. A. Barrios, and M. Lipson, “Guiding and confining light in void nanostructure,” Opt. Lett.29(11), 1209–1211 (2004). [CrossRef] [PubMed]
- R. F. Oulton, G. Bartal, D. F. P. Pile, and X. Zhang, “Confinement and propagation characteristics of subwavelength plasmonic modes,” N. J. Phys.10(10), 105018 (2008). [CrossRef]
- R. Buckley and P. Berini, “Figures of merit for 2D surface plasmon waveguides and application to metal stripes,” Opt. Express15(19), 12174–12182 (2007). [CrossRef] [PubMed]
Cited By |
 Alert me when this paper is cited |
OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.
« Previous Article | Next Article »
OSA is a member of 