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Polarization-independent actively tunable colour generation on imprinted plasmonic surfaces.

Franklin D, Chen Y, Vazquez-Guardado A, Modak S, Boroumand J, Xu D, Wu ST, Chanda D - Nat Commun (2015)

Bottom Line: Structural colour arising from nanostructured metallic surfaces offers many benefits compared to conventional pigmentation based display technologies, such as increased resolution and scalability of their optical response with structure dimensions.A large range of colour tunability is achieved over previous reports by utilizing an engineered surface which allows full liquid crystal reorientation while maximizing the overlap between plasmonic fields and liquid crystal.In combination with imprinted structures of varying periods, a full range of colours spanning the entire visible spectrum is achieved, paving the way towards dynamic pixels for reflective displays.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Physics, University of Central Florida, 4111 Libra Drive, Physical Sciences Building 430, Orlando, Florida 32816, USA [2] NanoScience Technology Center, University of Central Florida, 12424 Research Parkway Suite 400, Orlando, Florida 32826, USA.

ABSTRACT
Structural colour arising from nanostructured metallic surfaces offers many benefits compared to conventional pigmentation based display technologies, such as increased resolution and scalability of their optical response with structure dimensions. However, once these structures are fabricated their optical characteristics remain static, limiting their potential application. Here, by using a specially designed nanostructured plasmonic surface in conjunction with high birefringence liquid crystals, we demonstrate a tunable polarization-independent reflective surface where the colour of the surface is changed as a function of applied voltage. A large range of colour tunability is achieved over previous reports by utilizing an engineered surface which allows full liquid crystal reorientation while maximizing the overlap between plasmonic fields and liquid crystal. In combination with imprinted structures of varying periods, a full range of colours spanning the entire visible spectrum is achieved, paving the way towards dynamic pixels for reflective displays.

No MeSH data available.


Liquid crystal tunable plasmonic surface.(a) Schematic of the plasmonic-liquid crystal cell with impinging white light. Light transmits through the superstrate and liquid crystal layers to interact with the reflective plasmonic surface. The surface selectively absorbs light while reflecting the rest back out of the device. The wavelength of this absorption depends on the liquid crystal orientation near the interface which in turn depends on the electric field applied across the cell. (b) An applied electric field across the cell reorients the liquid crystal and changes the wavelengths of absorbed light.
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f1: Liquid crystal tunable plasmonic surface.(a) Schematic of the plasmonic-liquid crystal cell with impinging white light. Light transmits through the superstrate and liquid crystal layers to interact with the reflective plasmonic surface. The surface selectively absorbs light while reflecting the rest back out of the device. The wavelength of this absorption depends on the liquid crystal orientation near the interface which in turn depends on the electric field applied across the cell. (b) An applied electric field across the cell reorients the liquid crystal and changes the wavelengths of absorbed light.

Mentions: Figure 1 shows an illustration of the LC-plasmonic coupled system. The surface consists of a shallow imprinted array of nanowells coated with a continuous layer of aluminium. The surface is used as part of a LC cell, in which the nanostructured aluminium serves as a bottom electrode. The other half of the LC cell consists of an indium tin oxide (ITO) coated glass substrate, a polyimide alignment layer rubbed diagonally with respect to the grating vector of the plasmonic nanostructure, and chopped silica spacers. A high birefringence (Hi-Bi) LC is placed inside the cell in direct contact with the aluminium surface. Unpolarized white light transmits through the top glass and LC layers and couples to the plasmonic modes of the aluminium surface. The spectral location of these surface plasmon resonances (SPR) is dependent on the surrounding dielectric constant and is determined by the LC's orientation, which in turn, is controlled through the applied electric field between the ITO layer and aluminium surface. Light which is not absorbed by the surface is reflected back out of the LC cell to be perceived as a visible colour. Figure 1a,b illustrates a single surface as the LC reorients between its two extrema and the resulting colour change. This method differs greatly from standard LC displays in which colour is generated by static polymeric filters and the LC, in conjunction with polarization layers, functions as a light valve.


Polarization-independent actively tunable colour generation on imprinted plasmonic surfaces.

Franklin D, Chen Y, Vazquez-Guardado A, Modak S, Boroumand J, Xu D, Wu ST, Chanda D - Nat Commun (2015)

Liquid crystal tunable plasmonic surface.(a) Schematic of the plasmonic-liquid crystal cell with impinging white light. Light transmits through the superstrate and liquid crystal layers to interact with the reflective plasmonic surface. The surface selectively absorbs light while reflecting the rest back out of the device. The wavelength of this absorption depends on the liquid crystal orientation near the interface which in turn depends on the electric field applied across the cell. (b) An applied electric field across the cell reorients the liquid crystal and changes the wavelengths of absorbed light.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490413&req=5

f1: Liquid crystal tunable plasmonic surface.(a) Schematic of the plasmonic-liquid crystal cell with impinging white light. Light transmits through the superstrate and liquid crystal layers to interact with the reflective plasmonic surface. The surface selectively absorbs light while reflecting the rest back out of the device. The wavelength of this absorption depends on the liquid crystal orientation near the interface which in turn depends on the electric field applied across the cell. (b) An applied electric field across the cell reorients the liquid crystal and changes the wavelengths of absorbed light.
Mentions: Figure 1 shows an illustration of the LC-plasmonic coupled system. The surface consists of a shallow imprinted array of nanowells coated with a continuous layer of aluminium. The surface is used as part of a LC cell, in which the nanostructured aluminium serves as a bottom electrode. The other half of the LC cell consists of an indium tin oxide (ITO) coated glass substrate, a polyimide alignment layer rubbed diagonally with respect to the grating vector of the plasmonic nanostructure, and chopped silica spacers. A high birefringence (Hi-Bi) LC is placed inside the cell in direct contact with the aluminium surface. Unpolarized white light transmits through the top glass and LC layers and couples to the plasmonic modes of the aluminium surface. The spectral location of these surface plasmon resonances (SPR) is dependent on the surrounding dielectric constant and is determined by the LC's orientation, which in turn, is controlled through the applied electric field between the ITO layer and aluminium surface. Light which is not absorbed by the surface is reflected back out of the LC cell to be perceived as a visible colour. Figure 1a,b illustrates a single surface as the LC reorients between its two extrema and the resulting colour change. This method differs greatly from standard LC displays in which colour is generated by static polymeric filters and the LC, in conjunction with polarization layers, functions as a light valve.

Bottom Line: Structural colour arising from nanostructured metallic surfaces offers many benefits compared to conventional pigmentation based display technologies, such as increased resolution and scalability of their optical response with structure dimensions.A large range of colour tunability is achieved over previous reports by utilizing an engineered surface which allows full liquid crystal reorientation while maximizing the overlap between plasmonic fields and liquid crystal.In combination with imprinted structures of varying periods, a full range of colours spanning the entire visible spectrum is achieved, paving the way towards dynamic pixels for reflective displays.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Physics, University of Central Florida, 4111 Libra Drive, Physical Sciences Building 430, Orlando, Florida 32816, USA [2] NanoScience Technology Center, University of Central Florida, 12424 Research Parkway Suite 400, Orlando, Florida 32826, USA.

ABSTRACT
Structural colour arising from nanostructured metallic surfaces offers many benefits compared to conventional pigmentation based display technologies, such as increased resolution and scalability of their optical response with structure dimensions. However, once these structures are fabricated their optical characteristics remain static, limiting their potential application. Here, by using a specially designed nanostructured plasmonic surface in conjunction with high birefringence liquid crystals, we demonstrate a tunable polarization-independent reflective surface where the colour of the surface is changed as a function of applied voltage. A large range of colour tunability is achieved over previous reports by utilizing an engineered surface which allows full liquid crystal reorientation while maximizing the overlap between plasmonic fields and liquid crystal. In combination with imprinted structures of varying periods, a full range of colours spanning the entire visible spectrum is achieved, paving the way towards dynamic pixels for reflective displays.

No MeSH data available.