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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.


Fabricated structure and polarization analysis.(a) SEM image of the structure with period 300 nm before fabrication into liquid crystal cell and (b) a close up of the nanowell unit cell. Scale bars, (a) 500 nm, (b) 100 nm. (c) Optical image of macroscopically patterned ‘UCF' on a flexible PET substrate. (d) Reflection spectra of a 320-nm period metasurface for various polarization and voltage states. The polarization states are defined as the angle between the x-direction grating vector and the optical axis of the polarizer. Insets are microscope images depicting the reflected colour. Line colours are determined by the CIE colour-matching functions for the respective spectra.
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f3: Fabricated structure and polarization analysis.(a) SEM image of the structure with period 300 nm before fabrication into liquid crystal cell and (b) a close up of the nanowell unit cell. Scale bars, (a) 500 nm, (b) 100 nm. (c) Optical image of macroscopically patterned ‘UCF' on a flexible PET substrate. (d) Reflection spectra of a 320-nm period metasurface for various polarization and voltage states. The polarization states are defined as the angle between the x-direction grating vector and the optical axis of the polarizer. Insets are microscope images depicting the reflected colour. Line colours are determined by the CIE colour-matching functions for the respective spectra.

Mentions: Figure 3a,b shows a scanning electron microscope (SEM) image of the structured aluminium surface before LC cell assembly. A simple nanoimprinting technique is employed to pattern a polymer film (SU-8) followed by a blanket deposition of ∼30 nm aluminium using an electron beam evaporator. The master patterns are fabricated through direct laser writing (DLW). One such DLW master can produce hundreds of polymeric imprinting stamps, and one such stamp can produce thousands of imprints without any noticeable pattern degradation. The process is compatible with rigid as well as flexible substrates as can be seen in Fig. 3c, where a macroscopically patterned ‘UCF' LC-plasmonic surface is formed on a conformal plastic (polyethylene terephthalate (PET)) surface.


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)

Fabricated structure and polarization analysis.(a) SEM image of the structure with period 300 nm before fabrication into liquid crystal cell and (b) a close up of the nanowell unit cell. Scale bars, (a) 500 nm, (b) 100 nm. (c) Optical image of macroscopically patterned ‘UCF' on a flexible PET substrate. (d) Reflection spectra of a 320-nm period metasurface for various polarization and voltage states. The polarization states are defined as the angle between the x-direction grating vector and the optical axis of the polarizer. Insets are microscope images depicting the reflected colour. Line colours are determined by the CIE colour-matching functions for the respective spectra.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f3: Fabricated structure and polarization analysis.(a) SEM image of the structure with period 300 nm before fabrication into liquid crystal cell and (b) a close up of the nanowell unit cell. Scale bars, (a) 500 nm, (b) 100 nm. (c) Optical image of macroscopically patterned ‘UCF' on a flexible PET substrate. (d) Reflection spectra of a 320-nm period metasurface for various polarization and voltage states. The polarization states are defined as the angle between the x-direction grating vector and the optical axis of the polarizer. Insets are microscope images depicting the reflected colour. Line colours are determined by the CIE colour-matching functions for the respective spectra.
Mentions: Figure 3a,b shows a scanning electron microscope (SEM) image of the structured aluminium surface before LC cell assembly. A simple nanoimprinting technique is employed to pattern a polymer film (SU-8) followed by a blanket deposition of ∼30 nm aluminium using an electron beam evaporator. The master patterns are fabricated through direct laser writing (DLW). One such DLW master can produce hundreds of polymeric imprinting stamps, and one such stamp can produce thousands of imprints without any noticeable pattern degradation. The process is compatible with rigid as well as flexible substrates as can be seen in Fig. 3c, where a macroscopically patterned ‘UCF' LC-plasmonic surface is formed on a conformal plastic (polyethylene terephthalate (PET)) surface.

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.