Maskless Projection Lithography

Photolithography is a key element of the modem integrated circuit process. It is photolithography, combined with metal deposition, that allows a three dimensional circuit to be built up on a two dimensional surface. Since it is such an important part of the semiconductor manufacturing industry, a massive base of research in this area already exists. The problem with this pre-existing research is that it is geared solely toward industrial purposes, as opposed to more academic research areas. The goal of my research is to move this industrial process into the academic setting of Pomom College

Experimental Guardrail Installation

This is the final report on a limited investigation comparing the performance of painted steel, galvanized steel and aluminum guardrails. A previous report was issued in 1964. The final inspection of the project was made in November 1969. The project consisted of approximately 2500 lineal feet of each type of guardrail (see Figure 1 and Table 1). The painted steel and galvanized steel were installed in November 1962. The aluminum guardrails were installed in February 1963. All rails are the deep-beam type and were installed in accordance with special provisions which covered material requirements and erection procedures. The special provisions were included in the first report

Optical Apparatus and Method of Forming a Gradient Index Device

A refractive index device and method of making it include obtaining a glass structure comprising a plurality of nucleation sites. The glass structure is formed from a glass composition that comprises a first chemical component and a second chemical component. A crystal of the second chemical component has a different second refractive index from a first refractive index of the first chemical component. Each nucleation site defines where a crystal of the second chemical component can be grown. The method includes causing crystals of the second chemical component to grow in situ at a set of the plurality of nucleation sites in order to produce a spatial gradient of a refractive index in the glass structure

Substrate-blind photonic integration based on high-index glass materials

Conventional photonic integration technologies are inevitably substrate-dependent, as different substrate platforms stipulate vastly different device fabrication methods and processing compatibility requirements. Here we capitalize on the unique monolithic integration capacity of composition-engineered non-silicate glass materials (amorphous chalcogenides and transition metal oxides) to enable multifunctional, multi-layer photonic integration on virtually any technically important substrate platforms. We show that high-index glass film deposition and device fabrication can be performed at low temperatures ( < 250 °C) without compromising their low loss characteristics, and is thus fully compatible with monolithic integration on a broad range of substrates including semiconductors, plastics, textiles, and metals. Application of the technology is highlighted through three examples: demonstration of high-performance mid-IR photonic sensors on fluoride crystals, direct fabrication of photonic structures on graphene, and 3-D photonic integration on flexible plastic substrates.National Science Foundation (U.S.) (Award 1200406

Chalcogenide Glass-on-Graphene Photonics

Two-dimensional (2-D) materials are of tremendous interest to integrated photonics given their singular optical characteristics spanning light emission, modulation, saturable absorption, and nonlinear optics. To harness their optical properties, these atomically thin materials are usually attached onto prefabricated devices via a transfer process. In this paper, we present a new route for 2-D material integration with planar photonics. Central to this approach is the use of chalcogenide glass, a multifunctional material which can be directly deposited and patterned on a wide variety of 2-D materials and can simultaneously function as the light guiding medium, a gate dielectric, and a passivation layer for 2-D materials. Besides claiming improved fabrication yield and throughput compared to the traditional transfer process, our technique also enables unconventional multilayer device geometries optimally designed for enhancing light-matter interactions in the 2-D layers. Capitalizing on this facile integration method, we demonstrate a series of high-performance glass-on-graphene devices including ultra-broadband on-chip polarizers, energy-efficient thermo-optic switches, as well as graphene-based mid-infrared (mid-IR) waveguide-integrated photodetectors and modulators

Mid-infrared materials and devices on a Si platform for optical sensing

In this article, we review our recent work on mid-infrared (mid-IR) photonic materials and devices fabricated on silicon for on-chip sensing applications. Pedestal waveguides based on silicon are demonstrated as broadband mid-IR sensors. Our low-loss mid-IR directional couplers demonstrated in SiNx waveguides are useful in differential sensing applications. Photonic crystal cavities and microdisk resonators based on chalcogenide glasses for high sensitivity are also demonstrated as effective mid-IR sensors. Polymer-based functionalization layers, to enhance the sensitivity and selectivity of our sensor devices, are also presented. We discuss the design of mid-IR chalcogenide waveguides integrated with polycrystalline PbTe detectors on a monolithic silicon platform for optical sensing, wherein the use of a low-index spacer layer enables the evanescent coupling of mid-IR light from the waveguides to the detector. Finally, we show the successful fabrication processing of our first prototype mid-IR waveguide-integrated detectors