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Formation of broadband antireflective and superhydrophilic subwavelength structures on fused silica using one-step self-masking reactive ion etching.

Ye X, Jiang X, Huang J, Geng F, Sun L, Zu X, Wu W, Zheng W - Sci Rep (2015)

Bottom Line: The measured antireflection properties are consistent with the results of theoretical analysis using a finite-difference time-domain (FDTD) method.This method is also applicable to diffraction grating fabrication.Moreover, the surface of the subwavelength structures exhibits significant superhydrophilic properties.

View Article: PubMed Central - PubMed

Affiliation: Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang, 621900 (P.R. China).

ABSTRACT
Fused silica subwavelength structures (SWSs) with an average period of ~100 nm were fabricated using an efficient approach based on one-step self-masking reactive ion etching. The subwavelength structures exhibited excellent broadband antireflection properties from the ultraviolet to near-infrared wavelength range. These properties are attributable to the graded refractive index for the transition from air to the fused silica substrate that is produced by the ideal nanocone subwavelength structures. The transmittance in the 400-700 nm range increased from approximately 93% for the polished fused silica to greater than 99% for the subwavelength structure layer on fused silica. Achieving broadband antireflection in the visible and near-infrared wavelength range by appropriate matching of the SWS heights on the front and back sides of the fused silica is a novel strategy. The measured antireflection properties are consistent with the results of theoretical analysis using a finite-difference time-domain (FDTD) method. This method is also applicable to diffraction grating fabrication. Moreover, the surface of the subwavelength structures exhibits significant superhydrophilic properties.

No MeSH data available.


Two-dimensional contour plots of the calculated reflectance for various SWS shapes according to height and the wavelength of light:(A) truncated cone (50%), (B) truncated cone (25%), (C) cone, (D) paraboloid profiles.
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f5: Two-dimensional contour plots of the calculated reflectance for various SWS shapes according to height and the wavelength of light:(A) truncated cone (50%), (B) truncated cone (25%), (C) cone, (D) paraboloid profiles.

Mentions: Figure 5 presents the contour plots of the calculated reflectance result variations as a function of wavelength for the height of the SWS with (A) truncated cone (50%), (B) truncated cone (25%), (C) cone, and (D) paraboloid profiles. The three-dimensional simulation models of the structures that were used in this calculation are shown in the insets of Fig. 5. The corresponding structures were composed of a periodic pattern with a six-fold hexagonal symmetry for simplicity. As the height increased, the reflectance tended to decrease, and the low reflectance region was broadened toward longer wavelengths. These changes occurred because the effective refractive index changed more slowly. For the truncated cone, as the height increased from 0 to 500 nm, the reflectance oscillated in the 300–1400 nm wavelength region, indicating higher reflectance values of >1.5% (i.e., green parts). This oscillation was caused by interference between the upper and lower boundaries of the truncated cone, which acted as an effective medium (i.e., a single layer thin film with an abrupt change in the refractive index profile). However, the reflectance of the nanocones exhibit little dependence on height over a wide wavelength range of 300–1400 nm, thus indicating low reflectance values of <1% for heights greater than ~400 nm.


Formation of broadband antireflective and superhydrophilic subwavelength structures on fused silica using one-step self-masking reactive ion etching.

Ye X, Jiang X, Huang J, Geng F, Sun L, Zu X, Wu W, Zheng W - Sci Rep (2015)

Two-dimensional contour plots of the calculated reflectance for various SWS shapes according to height and the wavelength of light:(A) truncated cone (50%), (B) truncated cone (25%), (C) cone, (D) paraboloid profiles.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542686&req=5

f5: Two-dimensional contour plots of the calculated reflectance for various SWS shapes according to height and the wavelength of light:(A) truncated cone (50%), (B) truncated cone (25%), (C) cone, (D) paraboloid profiles.
Mentions: Figure 5 presents the contour plots of the calculated reflectance result variations as a function of wavelength for the height of the SWS with (A) truncated cone (50%), (B) truncated cone (25%), (C) cone, and (D) paraboloid profiles. The three-dimensional simulation models of the structures that were used in this calculation are shown in the insets of Fig. 5. The corresponding structures were composed of a periodic pattern with a six-fold hexagonal symmetry for simplicity. As the height increased, the reflectance tended to decrease, and the low reflectance region was broadened toward longer wavelengths. These changes occurred because the effective refractive index changed more slowly. For the truncated cone, as the height increased from 0 to 500 nm, the reflectance oscillated in the 300–1400 nm wavelength region, indicating higher reflectance values of >1.5% (i.e., green parts). This oscillation was caused by interference between the upper and lower boundaries of the truncated cone, which acted as an effective medium (i.e., a single layer thin film with an abrupt change in the refractive index profile). However, the reflectance of the nanocones exhibit little dependence on height over a wide wavelength range of 300–1400 nm, thus indicating low reflectance values of <1% for heights greater than ~400 nm.

Bottom Line: The measured antireflection properties are consistent with the results of theoretical analysis using a finite-difference time-domain (FDTD) method.This method is also applicable to diffraction grating fabrication.Moreover, the surface of the subwavelength structures exhibits significant superhydrophilic properties.

View Article: PubMed Central - PubMed

Affiliation: Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang, 621900 (P.R. China).

ABSTRACT
Fused silica subwavelength structures (SWSs) with an average period of ~100 nm were fabricated using an efficient approach based on one-step self-masking reactive ion etching. The subwavelength structures exhibited excellent broadband antireflection properties from the ultraviolet to near-infrared wavelength range. These properties are attributable to the graded refractive index for the transition from air to the fused silica substrate that is produced by the ideal nanocone subwavelength structures. The transmittance in the 400-700 nm range increased from approximately 93% for the polished fused silica to greater than 99% for the subwavelength structure layer on fused silica. Achieving broadband antireflection in the visible and near-infrared wavelength range by appropriate matching of the SWS heights on the front and back sides of the fused silica is a novel strategy. The measured antireflection properties are consistent with the results of theoretical analysis using a finite-difference time-domain (FDTD) method. This method is also applicable to diffraction grating fabrication. Moreover, the surface of the subwavelength structures exhibits significant superhydrophilic properties.

No MeSH data available.