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Silicon photonic crystal thermal emitter at near-infrared wavelengths.

O'Regan BJ, Wang Y, Krauss TF - Sci Rep (2015)

Bottom Line: The device is resistively heated by passing current through the photonic crystal membrane.At a temperature of ≈1100 K, we observe relatively sharp emission peaks with a Q factor around 18.A support structure system is implemented in order to achieve a large area suspended photonic crystal thermal emitter and electrical injection.

View Article: PubMed Central - PubMed

Affiliation: School of Physics &Astronomy, University of St Andrews, St Andrews, KY16 9SS, UK.

ABSTRACT
Controlling thermal emission with resonant photonic nanostructures has recently attracted much attention. Most of the work has concentrated on the mid-infrared wavelength range and/or was based on metallic nanostructures. Here, we demonstrate the experimental operation of a resonant thermal emitter operating in the near-infrared (≈1.5 μm) wavelength range. The emitter is based on a doped silicon photonic crystal consisting of a two dimensional square array of holes and using silicon-on-insulator technology with a device-layer thickness of 220 nm. The device is resistively heated by passing current through the photonic crystal membrane. At a temperature of ≈1100 K, we observe relatively sharp emission peaks with a Q factor around 18. A support structure system is implemented in order to achieve a large area suspended photonic crystal thermal emitter and electrical injection. The device demonstrates that weak absorption together with photonic resonances can be used as a wavelength-selection mechanism for thermal emitters, both for the enhancement and the suppression of emission.

No MeSH data available.


Related in: MedlinePlus

Simulated optical properties of the 2D PhC slab.(a) Reflectance spectrum for intrinsic (undoped) silicon at normal incidence obtained by FE simulation. (b) Simulated reflectance and absorptance spectrum for a doped (doping concentration of 2.5 × 1020 cm−3) PhC slab at normal incidence with dispersion as in reference [16] using the FE method. (c) Bandstructure computed using 3D FDTD MEEP software for the highly doped PhC structure. The shaded region indicates the area below the light line. (d) Illustrates the high symmetry points of the square hole array lattice. (e) Illustrates the computational domain used. The parameter values used were a = 605 nm, r = 133 nm and d = 220 nm. The computation domain was the same in both methods except for the source. For FE method the source was a plane wave excited from the top of the domain; while in the FDTD calculation a point source within the slab itself was used.
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f3: Simulated optical properties of the 2D PhC slab.(a) Reflectance spectrum for intrinsic (undoped) silicon at normal incidence obtained by FE simulation. (b) Simulated reflectance and absorptance spectrum for a doped (doping concentration of 2.5 × 1020 cm−3) PhC slab at normal incidence with dispersion as in reference [16] using the FE method. (c) Bandstructure computed using 3D FDTD MEEP software for the highly doped PhC structure. The shaded region indicates the area below the light line. (d) Illustrates the high symmetry points of the square hole array lattice. (e) Illustrates the computational domain used. The parameter values used were a = 605 nm, r = 133 nm and d = 220 nm. The computation domain was the same in both methods except for the source. For FE method the source was a plane wave excited from the top of the domain; while in the FDTD calculation a point source within the slab itself was used.

Mentions: The optical properties of the photonic structure were first assessed using a 3D finite element (FE) model implemented using the COMSOL® Multiphysics software package17. We simulated a normal reflection spectrum for the PhC slab suspended in air both for intrinsic (undoped, n = 3.5) silicon and for the n-type doped (2.5 × 1020 cm−3) case with dispersion as described in reference [16]. A schematic of the computational domain, with a single unit cell of the PhC slab, is shown in Fig. 3(e). The boundary conditions were set as follows: perfectly matched absorbing layers were used on the top and bottom surfaces with periodic boundary conditions imposed in both the x and y directions perpendicular to the slab. An incident plane wave was excited from the top surface of the computational domain. Figure 3(a) (undoped) and Fig. 3(b) (doped) shows the reflection spectrum for a PhC with period (a) of 605 nm, hole radius (r) of 133 nm and slab thickness (d) of 220 nm. The undoped reflection spectrum, (Fig. 3(a)), shows sharp resonance features. These features represent the quasi-guided resonances of the slab18. When doping is introduced, (Fig. 3(b)), the resonances blue-shift due to the reduced refractive index, and they broaden due to the presence of loss. To further assess the PhC structure, 3D finite difference time domain (FDTD) calculations were carried out to construct the photonic bandstructure for the doped case (n = 3.31), using the 3D FDTD software known as MEEP19. For the FDTD calculations, the computational domain and boundary conditions were identical to the ones used for the FE method calculations except for the light source. For the FDTD calculations, a dipole source was placed at various positions across the z = 0 plane of the slab. This ensured that the source coupled to all of the possible modes at each k-point and a complete band diagram was obtained, see Fig. 3(c). We observe three optical resonances in reflection for the undoped case, while in the doped case, three absorption resonances. These peaks correspond to points A, B, and C along the Gamma point of the bandstructure. The absorptance of each of the three peaks is approximately 0.5, which is expected from coupled mode theory for such structures when the critical coupling condition applies20, in other words, when the coupling loss and the absorption loss in the structure are equal.


Silicon photonic crystal thermal emitter at near-infrared wavelengths.

O'Regan BJ, Wang Y, Krauss TF - Sci Rep (2015)

Simulated optical properties of the 2D PhC slab.(a) Reflectance spectrum for intrinsic (undoped) silicon at normal incidence obtained by FE simulation. (b) Simulated reflectance and absorptance spectrum for a doped (doping concentration of 2.5 × 1020 cm−3) PhC slab at normal incidence with dispersion as in reference [16] using the FE method. (c) Bandstructure computed using 3D FDTD MEEP software for the highly doped PhC structure. The shaded region indicates the area below the light line. (d) Illustrates the high symmetry points of the square hole array lattice. (e) Illustrates the computational domain used. The parameter values used were a = 605 nm, r = 133 nm and d = 220 nm. The computation domain was the same in both methods except for the source. For FE method the source was a plane wave excited from the top of the domain; while in the FDTD calculation a point source within the slab itself was used.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4544018&req=5

f3: Simulated optical properties of the 2D PhC slab.(a) Reflectance spectrum for intrinsic (undoped) silicon at normal incidence obtained by FE simulation. (b) Simulated reflectance and absorptance spectrum for a doped (doping concentration of 2.5 × 1020 cm−3) PhC slab at normal incidence with dispersion as in reference [16] using the FE method. (c) Bandstructure computed using 3D FDTD MEEP software for the highly doped PhC structure. The shaded region indicates the area below the light line. (d) Illustrates the high symmetry points of the square hole array lattice. (e) Illustrates the computational domain used. The parameter values used were a = 605 nm, r = 133 nm and d = 220 nm. The computation domain was the same in both methods except for the source. For FE method the source was a plane wave excited from the top of the domain; while in the FDTD calculation a point source within the slab itself was used.
Mentions: The optical properties of the photonic structure were first assessed using a 3D finite element (FE) model implemented using the COMSOL® Multiphysics software package17. We simulated a normal reflection spectrum for the PhC slab suspended in air both for intrinsic (undoped, n = 3.5) silicon and for the n-type doped (2.5 × 1020 cm−3) case with dispersion as described in reference [16]. A schematic of the computational domain, with a single unit cell of the PhC slab, is shown in Fig. 3(e). The boundary conditions were set as follows: perfectly matched absorbing layers were used on the top and bottom surfaces with periodic boundary conditions imposed in both the x and y directions perpendicular to the slab. An incident plane wave was excited from the top surface of the computational domain. Figure 3(a) (undoped) and Fig. 3(b) (doped) shows the reflection spectrum for a PhC with period (a) of 605 nm, hole radius (r) of 133 nm and slab thickness (d) of 220 nm. The undoped reflection spectrum, (Fig. 3(a)), shows sharp resonance features. These features represent the quasi-guided resonances of the slab18. When doping is introduced, (Fig. 3(b)), the resonances blue-shift due to the reduced refractive index, and they broaden due to the presence of loss. To further assess the PhC structure, 3D finite difference time domain (FDTD) calculations were carried out to construct the photonic bandstructure for the doped case (n = 3.31), using the 3D FDTD software known as MEEP19. For the FDTD calculations, the computational domain and boundary conditions were identical to the ones used for the FE method calculations except for the light source. For the FDTD calculations, a dipole source was placed at various positions across the z = 0 plane of the slab. This ensured that the source coupled to all of the possible modes at each k-point and a complete band diagram was obtained, see Fig. 3(c). We observe three optical resonances in reflection for the undoped case, while in the doped case, three absorption resonances. These peaks correspond to points A, B, and C along the Gamma point of the bandstructure. The absorptance of each of the three peaks is approximately 0.5, which is expected from coupled mode theory for such structures when the critical coupling condition applies20, in other words, when the coupling loss and the absorption loss in the structure are equal.

Bottom Line: The device is resistively heated by passing current through the photonic crystal membrane.At a temperature of ≈1100 K, we observe relatively sharp emission peaks with a Q factor around 18.A support structure system is implemented in order to achieve a large area suspended photonic crystal thermal emitter and electrical injection.

View Article: PubMed Central - PubMed

Affiliation: School of Physics &Astronomy, University of St Andrews, St Andrews, KY16 9SS, UK.

ABSTRACT
Controlling thermal emission with resonant photonic nanostructures has recently attracted much attention. Most of the work has concentrated on the mid-infrared wavelength range and/or was based on metallic nanostructures. Here, we demonstrate the experimental operation of a resonant thermal emitter operating in the near-infrared (≈1.5 μm) wavelength range. The emitter is based on a doped silicon photonic crystal consisting of a two dimensional square array of holes and using silicon-on-insulator technology with a device-layer thickness of 220 nm. The device is resistively heated by passing current through the photonic crystal membrane. At a temperature of ≈1100 K, we observe relatively sharp emission peaks with a Q factor around 18. A support structure system is implemented in order to achieve a large area suspended photonic crystal thermal emitter and electrical injection. The device demonstrates that weak absorption together with photonic resonances can be used as a wavelength-selection mechanism for thermal emitters, both for the enhancement and the suppression of emission.

No MeSH data available.


Related in: MedlinePlus