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Demonstration of nanoimprinted hyperlens array for high-throughput sub-diffraction imaging

View Article: PubMed Central - PubMed

ABSTRACT

Overcoming the resolution limit of conventional optics is regarded as the most important issue in optical imaging science and technology. Although hyperlenses, super-resolution imaging devices based on highly anisotropic dispersion relations that allow the access of high-wavevector components, have recently achieved far-field sub-diffraction imaging in real-time, the previously demonstrated devices have suffered from the extreme difficulties of both the fabrication process and the non-artificial objects placement. This results in restrictions on the practical applications of the hyperlens devices. While implementing large-scale hyperlens arrays in conventional microscopy is desirable to solve such issues, it has not been feasible to fabricate such large-scale hyperlens array with the previously used nanofabrication methods. Here, we suggest a scalable and reliable fabrication process of a large-scale hyperlens device based on direct pattern transfer techniques. We fabricate a 5 cm × 5 cm size hyperlenses array and experimentally demonstrate that it can resolve sub-diffraction features down to 160 nm under 410 nm wavelength visible light. The array-based hyperlens device will provide a simple solution for much more practical far-field and real-time super-resolution imaging which can be widely used in optics, biology, medical science, nanotechnology and other closely related interdisciplinary fields.

No MeSH data available.


SEM images of the detailed step-by-step master mold fabrication process.(a,b) SEM images of the top and cross-section views, respectively, after the lift-off process for a hexagonal array of hole patterns with the dimensions of 700 nm diameter and 3 μm pitch at the Cr layer. (c,d) SEM images of the top and cross-section views, respectively, after the ICP process for a 750 nm diameter and 3 μm pitch hole patterns at the quartz substrate. (e,f) SEM images of the top and cross-section views after all process is finished. Half-spherical patterns array is well defined.
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f3: SEM images of the detailed step-by-step master mold fabrication process.(a,b) SEM images of the top and cross-section views, respectively, after the lift-off process for a hexagonal array of hole patterns with the dimensions of 700 nm diameter and 3 μm pitch at the Cr layer. (c,d) SEM images of the top and cross-section views, respectively, after the ICP process for a 750 nm diameter and 3 μm pitch hole patterns at the quartz substrate. (e,f) SEM images of the top and cross-section views after all process is finished. Half-spherical patterns array is well defined.

Mentions: Figure 3 shows the scanning electron microscopy (SEM) images of each process. Figure 3(a) and (b) are the top and tilted cross-section view, respectively, of the opened Cr mask patterns after the lift-off process. The Cr mask layer is etched by the ICP process, in the shape of hexagonally arrayed hole patterns. The diameter, pitch, and thickness of the hole patterns are 700 nm, 3 μm, and 100 nm, respectively. The hole patterns are made perfectly over the entire area. Figure 3(c) and (d) show the SEM images of the vertically etched process of the quartz. Using the Cr layer as a mask, the quartz substrate is etched selectively. The diameter and the depth of the hole patterns are 750 nm and 450 nm, respectively. Figure 3(e) and (f) are the SEM images after the wet-etching process and the removal of the Cr mask. The quartz is selectively and isotropically wet-etched by using 5:1 buffered oxide etchant (BOE). The master quartz stamp of the HAHS patterns is perfectly fabricated with the large size of 5 cm × 5 cm without any deformation. The diameter of the hemisphere patterns is 2.5 μm and the depth is 1.7 μm, which are used as the base dimensions of the hyperlens device.


Demonstration of nanoimprinted hyperlens array for high-throughput sub-diffraction imaging
SEM images of the detailed step-by-step master mold fabrication process.(a,b) SEM images of the top and cross-section views, respectively, after the lift-off process for a hexagonal array of hole patterns with the dimensions of 700 nm diameter and 3 μm pitch at the Cr layer. (c,d) SEM images of the top and cross-section views, respectively, after the ICP process for a 750 nm diameter and 3 μm pitch hole patterns at the quartz substrate. (e,f) SEM images of the top and cross-section views after all process is finished. Half-spherical patterns array is well defined.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5385565&req=5

f3: SEM images of the detailed step-by-step master mold fabrication process.(a,b) SEM images of the top and cross-section views, respectively, after the lift-off process for a hexagonal array of hole patterns with the dimensions of 700 nm diameter and 3 μm pitch at the Cr layer. (c,d) SEM images of the top and cross-section views, respectively, after the ICP process for a 750 nm diameter and 3 μm pitch hole patterns at the quartz substrate. (e,f) SEM images of the top and cross-section views after all process is finished. Half-spherical patterns array is well defined.
Mentions: Figure 3 shows the scanning electron microscopy (SEM) images of each process. Figure 3(a) and (b) are the top and tilted cross-section view, respectively, of the opened Cr mask patterns after the lift-off process. The Cr mask layer is etched by the ICP process, in the shape of hexagonally arrayed hole patterns. The diameter, pitch, and thickness of the hole patterns are 700 nm, 3 μm, and 100 nm, respectively. The hole patterns are made perfectly over the entire area. Figure 3(c) and (d) show the SEM images of the vertically etched process of the quartz. Using the Cr layer as a mask, the quartz substrate is etched selectively. The diameter and the depth of the hole patterns are 750 nm and 450 nm, respectively. Figure 3(e) and (f) are the SEM images after the wet-etching process and the removal of the Cr mask. The quartz is selectively and isotropically wet-etched by using 5:1 buffered oxide etchant (BOE). The master quartz stamp of the HAHS patterns is perfectly fabricated with the large size of 5 cm × 5 cm without any deformation. The diameter of the hemisphere patterns is 2.5 μm and the depth is 1.7 μm, which are used as the base dimensions of the hyperlens device.

View Article: PubMed Central - PubMed

ABSTRACT

Overcoming the resolution limit of conventional optics is regarded as the most important issue in optical imaging science and technology. Although hyperlenses, super-resolution imaging devices based on highly anisotropic dispersion relations that allow the access of high-wavevector components, have recently achieved far-field sub-diffraction imaging in real-time, the previously demonstrated devices have suffered from the extreme difficulties of both the fabrication process and the non-artificial objects placement. This results in restrictions on the practical applications of the hyperlens devices. While implementing large-scale hyperlens arrays in conventional microscopy is desirable to solve such issues, it has not been feasible to fabricate such large-scale hyperlens array with the previously used nanofabrication methods. Here, we suggest a scalable and reliable fabrication process of a large-scale hyperlens device based on direct pattern transfer techniques. We fabricate a 5 cm × 5 cm size hyperlenses array and experimentally demonstrate that it can resolve sub-diffraction features down to 160 nm under 410 nm wavelength visible light. The array-based hyperlens device will provide a simple solution for much more practical far-field and real-time super-resolution imaging which can be widely used in optics, biology, medical science, nanotechnology and other closely related interdisciplinary fields.

No MeSH data available.