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High-throughput nanofabrication of infra-red and chiral metamaterials using nanospherical-lens lithography.

Chang YC, Lu SC, Chung HC, Wang SM, Tsai TD, Guo TF - Sci Rep (2013)

Bottom Line: By replacing the light source with a hand-held ultraviolet lamp, its asymmetric light emission pattern produces the elliptical-shaped photoresist holes after passing through the spheres.The long axis of the ellipse is parallel to the lamp direction.This method is both high-throughput and low-cost, which is a powerful tool for future infra-red metamaterials applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Photonics and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan.

ABSTRACT
Various infra-red and planar chiral metamaterials were fabricated using the modified Nanospherical-Lens Lithography. By replacing the light source with a hand-held ultraviolet lamp, its asymmetric light emission pattern produces the elliptical-shaped photoresist holes after passing through the spheres. The long axis of the ellipse is parallel to the lamp direction. The fabricated ellipse arrays exhibit localized surface plasmon resonance in mid-infra-red and are ideal platforms for surface enhanced infra-red absorption (SEIRA). We also demonstrate a way to design and fabricate complicated patterns by tuning parameters in each exposure step. This method is both high-throughput and low-cost, which is a powerful tool for future infra-red metamaterials applications.

No MeSH data available.


Related in: MedlinePlus

SEM images of the nanostructures fabricated.(a1) to (a3) all with E1(0 cm, 0°, 100 s) and varying exposure duration so E2(0 cm, 90°, 100 s), E2(0 cm, 90°, 80 s), E2(0 cm, 90°, 60 s), respectively. (b1) to (b3) are results after E1(0 cm, 0°, 100 s) and varying the shift distance (Sx) so E2(3 cm, 90°, 100 s), E2(6 cm, 90°, 100 s), E2(7.5 cm, 90°, 100 s), respectively. (c1) to (c3) are results after single, double, and triple exposures by rotating the lamp 60° after each exposure. The exposure durations are all 100 s. (d1) E1(0 cm, 0°, 100 s)/E2(7.5 cm, 90°, 360 s) (d2) E1(0 cm, 0°, 100 s)/E2(7.5 cm, 90°, 300 s)/E3(7.5 cm, −90°, 360 s) (d3) E1(6 cm, 0°, 300 s)/E2(6 cm, 90°, 300 s)/E3(6 cm, 180°, 300 s) (e1) to (e4) are possible planar chiral metamaterials that can be fabricated. (e1) and (e2) E1(0 cm, 0°, 150 s)/E2(7.5 cm, ±90°, 300 s). (e3) and (e4) E1(0 cm, ±45°, 100 s)/E2(7 cm, 90°, 300 s)/E3(7 cm, −90°, 300 s). The Au thickness of all the nanostructures is 15 nm and the scale bar indicates 2 μm.
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f6: SEM images of the nanostructures fabricated.(a1) to (a3) all with E1(0 cm, 0°, 100 s) and varying exposure duration so E2(0 cm, 90°, 100 s), E2(0 cm, 90°, 80 s), E2(0 cm, 90°, 60 s), respectively. (b1) to (b3) are results after E1(0 cm, 0°, 100 s) and varying the shift distance (Sx) so E2(3 cm, 90°, 100 s), E2(6 cm, 90°, 100 s), E2(7.5 cm, 90°, 100 s), respectively. (c1) to (c3) are results after single, double, and triple exposures by rotating the lamp 60° after each exposure. The exposure durations are all 100 s. (d1) E1(0 cm, 0°, 100 s)/E2(7.5 cm, 90°, 360 s) (d2) E1(0 cm, 0°, 100 s)/E2(7.5 cm, 90°, 300 s)/E3(7.5 cm, −90°, 360 s) (d3) E1(6 cm, 0°, 300 s)/E2(6 cm, 90°, 300 s)/E3(6 cm, 180°, 300 s) (e1) to (e4) are possible planar chiral metamaterials that can be fabricated. (e1) and (e2) E1(0 cm, 0°, 150 s)/E2(7.5 cm, ±90°, 300 s). (e3) and (e4) E1(0 cm, ±45°, 100 s)/E2(7 cm, 90°, 300 s)/E3(7 cm, −90°, 300 s). The Au thickness of all the nanostructures is 15 nm and the scale bar indicates 2 μm.

Mentions: Fig. 6 illustrates the scanning electron microscopy (SEM) images of different shapes of structures that can be fabricated using the proposed method. Fig. 6(a1) demonstrates a cross array fabricated by performing the 2nd UV exposure after rotating the lamp for 90°. The durations for both exposures are 100 s and the resulting cross structures exhibit two legs with similar length. The length for each leg can be separately controlled by changing the duration for each UV exposure. Figs. 6(a2) and (a3) demonstrate two un-even cross arrays which exhibit two different leg lengths. In both figures, the 1st exposure for both samples are kept the same at 100 s and the 2nd exposure is reduced to 80 s and 60 s, respectively. It is possible to fabricate a cross structure with an offset center position. This can be simply done by changing the sample position and then performing the 2nd exposure. The durations for the first and second exposures for all the samples are set as 100 s. Figs. 6(b1) to (b2) illustrated the SEM images of the resulting cross arrays. The shift of the second leg is clearly observed in each image and the shift becomes larger when Sx becomes larger. The shift is about 140 nm when Sx is 3 cm and increases to 450 nm when Sx is 7.5 cm. It should also be noted that the length of the second leg becomes shorter as the shift of sample location becomes larger, which is reasonable since the sample is further away from the lamp.


High-throughput nanofabrication of infra-red and chiral metamaterials using nanospherical-lens lithography.

Chang YC, Lu SC, Chung HC, Wang SM, Tsai TD, Guo TF - Sci Rep (2013)

SEM images of the nanostructures fabricated.(a1) to (a3) all with E1(0 cm, 0°, 100 s) and varying exposure duration so E2(0 cm, 90°, 100 s), E2(0 cm, 90°, 80 s), E2(0 cm, 90°, 60 s), respectively. (b1) to (b3) are results after E1(0 cm, 0°, 100 s) and varying the shift distance (Sx) so E2(3 cm, 90°, 100 s), E2(6 cm, 90°, 100 s), E2(7.5 cm, 90°, 100 s), respectively. (c1) to (c3) are results after single, double, and triple exposures by rotating the lamp 60° after each exposure. The exposure durations are all 100 s. (d1) E1(0 cm, 0°, 100 s)/E2(7.5 cm, 90°, 360 s) (d2) E1(0 cm, 0°, 100 s)/E2(7.5 cm, 90°, 300 s)/E3(7.5 cm, −90°, 360 s) (d3) E1(6 cm, 0°, 300 s)/E2(6 cm, 90°, 300 s)/E3(6 cm, 180°, 300 s) (e1) to (e4) are possible planar chiral metamaterials that can be fabricated. (e1) and (e2) E1(0 cm, 0°, 150 s)/E2(7.5 cm, ±90°, 300 s). (e3) and (e4) E1(0 cm, ±45°, 100 s)/E2(7 cm, 90°, 300 s)/E3(7 cm, −90°, 300 s). The Au thickness of all the nanostructures is 15 nm and the scale bar indicates 2 μm.
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f6: SEM images of the nanostructures fabricated.(a1) to (a3) all with E1(0 cm, 0°, 100 s) and varying exposure duration so E2(0 cm, 90°, 100 s), E2(0 cm, 90°, 80 s), E2(0 cm, 90°, 60 s), respectively. (b1) to (b3) are results after E1(0 cm, 0°, 100 s) and varying the shift distance (Sx) so E2(3 cm, 90°, 100 s), E2(6 cm, 90°, 100 s), E2(7.5 cm, 90°, 100 s), respectively. (c1) to (c3) are results after single, double, and triple exposures by rotating the lamp 60° after each exposure. The exposure durations are all 100 s. (d1) E1(0 cm, 0°, 100 s)/E2(7.5 cm, 90°, 360 s) (d2) E1(0 cm, 0°, 100 s)/E2(7.5 cm, 90°, 300 s)/E3(7.5 cm, −90°, 360 s) (d3) E1(6 cm, 0°, 300 s)/E2(6 cm, 90°, 300 s)/E3(6 cm, 180°, 300 s) (e1) to (e4) are possible planar chiral metamaterials that can be fabricated. (e1) and (e2) E1(0 cm, 0°, 150 s)/E2(7.5 cm, ±90°, 300 s). (e3) and (e4) E1(0 cm, ±45°, 100 s)/E2(7 cm, 90°, 300 s)/E3(7 cm, −90°, 300 s). The Au thickness of all the nanostructures is 15 nm and the scale bar indicates 2 μm.
Mentions: Fig. 6 illustrates the scanning electron microscopy (SEM) images of different shapes of structures that can be fabricated using the proposed method. Fig. 6(a1) demonstrates a cross array fabricated by performing the 2nd UV exposure after rotating the lamp for 90°. The durations for both exposures are 100 s and the resulting cross structures exhibit two legs with similar length. The length for each leg can be separately controlled by changing the duration for each UV exposure. Figs. 6(a2) and (a3) demonstrate two un-even cross arrays which exhibit two different leg lengths. In both figures, the 1st exposure for both samples are kept the same at 100 s and the 2nd exposure is reduced to 80 s and 60 s, respectively. It is possible to fabricate a cross structure with an offset center position. This can be simply done by changing the sample position and then performing the 2nd exposure. The durations for the first and second exposures for all the samples are set as 100 s. Figs. 6(b1) to (b2) illustrated the SEM images of the resulting cross arrays. The shift of the second leg is clearly observed in each image and the shift becomes larger when Sx becomes larger. The shift is about 140 nm when Sx is 3 cm and increases to 450 nm when Sx is 7.5 cm. It should also be noted that the length of the second leg becomes shorter as the shift of sample location becomes larger, which is reasonable since the sample is further away from the lamp.

Bottom Line: By replacing the light source with a hand-held ultraviolet lamp, its asymmetric light emission pattern produces the elliptical-shaped photoresist holes after passing through the spheres.The long axis of the ellipse is parallel to the lamp direction.This method is both high-throughput and low-cost, which is a powerful tool for future infra-red metamaterials applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Photonics and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan.

ABSTRACT
Various infra-red and planar chiral metamaterials were fabricated using the modified Nanospherical-Lens Lithography. By replacing the light source with a hand-held ultraviolet lamp, its asymmetric light emission pattern produces the elliptical-shaped photoresist holes after passing through the spheres. The long axis of the ellipse is parallel to the lamp direction. The fabricated ellipse arrays exhibit localized surface plasmon resonance in mid-infra-red and are ideal platforms for surface enhanced infra-red absorption (SEIRA). We also demonstrate a way to design and fabricate complicated patterns by tuning parameters in each exposure step. This method is both high-throughput and low-cost, which is a powerful tool for future infra-red metamaterials applications.

No MeSH data available.


Related in: MedlinePlus