Biomedical subjects

Xuegong Deng

Publications and source records attributed to Xuegong Deng.

6 recordsLinked to original sources

PubMed2006

Ultraviolet wave plates based on monolithic integration of two fully filled and planarized nanograting layers.

We successfully fabricated a high-performance half-wave plate for the 405 nm wavelength based on monolithic integration of two nanograting layers. Each of the nanograting layers functions as a quarter-wave plate. Both of the nanograting layers were fully filled and planarized to achieve the monolithic integration. UV-nanoimprint lithography, along with thin-film deposition, high-aspect-ratio reactive ion etching, and trench-filling technologies, was used in fabrication and integration of the individual nanograting layers. High-aspect-ratio nanogratings with sub-50 nm linewidths and 100 nm spacing were fabricated to achieve good optical performance at the near-UV wavelength. The ability to integrate multiple nanostructure-based optical layers opens a path for integrated multifunction devices, as well as a new strategy for driving both miniaturization and cost.

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PubMed2006

Wideband antireflective polarizers based on integrated diffractive multilayer microstructures.

Microstructures of composite materials can exhibit properties significantly different from their individual constitution. By utilizing these unique characteristics, we design diffractive optical elements to demonstrate transmission-only polarizers for telecommunications. The transmittance and the extinction ratio of the proposed structure are >95% and >40 dB at 1470-1910 nm wavelengths, respectively. The average reflectance for random polarization is less than 1% at 1350-1580 nm. The methods are applicable to diffractive optics, e.g., in the ultraviolet and visible spectrum.

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PubMed2006

Large area, 38 nm half-pitch grating fabrication by using atomic spacer lithography from aluminum wire grids.

We wrapped 150 nm period aluminum wire grid polarizer (WGP) with AlSiOx by using atomic layer deposition at 250 degrees C. The nanometer precision coating defined the spacer to double the spatial frequency of the 100 mm diameter grating fabricated by using a legacy immersion holography setup at 351 nm wavelength. Half-pitch grating of approximately 38 nm was demonstrated with good pattern uniformity, excellent repeatability, and a wide processing window. We believe 10 nm half-pitch grating over even larger areas are viable, overcoming one major hurdle to commercialize nanoimprint.

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PubMed2005

Achromatic wave plates for optical pickup units fabricated by use of imprint lithography.

We report achromatic form-birefringence wave plates for optical pickup units. Material dispersion and structure dispersion are balanced in a rigorous multilayer design. A trilayer grating using SiN(x)/SiO(y)N(z)/SiO2 provides easily accessible process control points and relaxed fabrication tolerance. We demonstrate precise patterning by using nanoimprint lithography on UV-curable polymers, alleviating a major fabrication challenge. The achromatic wave plates exhibit 90+/-3 degrees retardance and >95% transmittance as measured by a Mueller matrix method at wavelengths of 640-800 nm.

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PubMed2005

High-performance optical retarders based on all-dielectric immersion nanogratings.

High-performance true zero-order optical retarders were realized based on all-dielectric immersion nanogratings. All-dielectric nanolaminate materials, deposited by atomic layer deposition, were utilized to fill the trenches of the nanogratings to form immersion nanogratings. The refractive index of the nanolaminate material can be dialed and controlled precisely by controlling the ratio of the two compositions forming the nanolaminate material. This significantly improves the design and process windows for realizing precise optical retarders, particularly very-low-phase retarders. Three 100-mm-diameter very-low-phase retarders with highly precise and uniform phase retardance and very high transmittance were realized by use of the all-dielectric immersion grating design and an atomic layer deposition technique.

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PubMed2005

High-performance nanowire-grid polarizers.

We developed a new type of wire-grid polarizer that has achieved excellent optical performance and reliability. The nanowire-grid polarizer is based on a fully optimized innovative design structure that consists of not only the core nanowire grid but also the surrounding multilayer thin-film structures. The surrounding structures are designed for antireflectivity to provide the best possible efficiency as well as for device reliability to provide the best possible handling robustness and environmental durability. The core nanowire grid utilizes nanosized high-aspect-ratio dielectric walls as a support for forming a high-aspect-ratio metal nanowire grid that significantly reduces energy loss as a result of metal absorption for the transmitted beam while providing a high extinction ratio of the blocked beam. The developed high-quality nanowire-grid polarizer has potential for use in many integrated optical applications.

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