Agency: Department of Defense | Branch: Army | Program: STTR | Phase: Phase I | Award Amount: 150.00K | Year: 2013
This project will develop plasmonic films that perform the dual functions of optical filtering and electrical conduction for solar-blind ultraviolet radiation (UV) detectors. Two types of plasmonic structures will be investigated, namely nano-hole arrays in an aluminum film atop UV radiation detecting semiconductors. These two similar plasmonic structures support different types of surface plasmons in the UV spectral range, namely localized or non-localized surface plasmons. The films will block visible and infrared light and allow UV light to be transmitted to any UV detecting substrate, and the film will then conduct the photo-generated electrical current. The benefit of a single layer structure that performs both optical filtering and electrical conduction is that it allows for lower cost, more robust, lighter weight solar-blind UV detectors that can be designed to address numerous UV sensing markets and applications. The structures will be designed towards eventual use in the detection of missile plumes, and the large commercial markets of water and food purification systems, and flame sensors. In Phase I, the plasmonic structures will be designed and modeled, fabricated and tested. The project team includes Phoebus Optoelectronics, the National Science Foundation's Center for Metamaterials at the City University of New York, and Raytheon.
Agency: Department of Defense | Branch: Defense Advanced Research Projects Agency | Program: SBIR | Phase: Phase II | Award Amount: 747.11K | Year: 2011
The objective of proposed Phase II project is to develop multi-junction Graetzel cells using a cost effective, single layer metamaterial light harvesting template into which, up to four different sets of wavelength-selective ruthenium dye complexes are deposited. The light harvesting template performs three roles: (1) spectral band splitting of the incident solar spectrum into different cavities into which different wavelength specific ruthenium compounds have been electrodeposited, (2) light concentration, and (3) serves as a heat sink to avoid the harmful effects of high temperatures. These three improvements to the traditional Graetzel cell are expected to increase the efficiency to 42% compared to ~11% for traditional Graetzel cells, resulting in a predicted module cost of 95/Watt. Certain untested aspects of our device may increase the efficiency to as high as 60%, resulting in a cost reduction to 66/Watt.
Agency: Department of Defense | Branch: Office for Chemical and Biological Defense | Program: SBIR | Phase: Phase I | Award Amount: 150.00K | Year: 2011
We propose a metamaterial-enhanced microbolometer with strong absorption over a narrow band that is dynamically tunable over the 8-10 micron band. A single-layer photonic metamaterial consisting of a thin metal film perforated with a 2-D array of dielectric apertures will be deposited on an amorphous-Silicon layer acting as an absorber and bolometer. The metamaterial, in conjunction with planar dielectric layers below the absorber, will trap and concentrate a narrow frequency band within the absorbing layer while strongly reflecting out-of-band light. This design is based on a previously developed metamaterial-enhanced Si photodiode that exhibited strong absorption over a narrow width (1% of the central frequency). Tuning the absorption band across the 8-10 micron range may be achieved via MEMS actuation applied to a standard air-bridge microbolometer structure. The metamaterial may be fabricated with standard photolithography, as we have demonstrated previously, and the rest of the fabrication involves materials and processes that are standard for microbolometers. We believe this structure offers considerable advantages over a multi-layer coupled split-ring and cut wire perfect absorber approach, including: ease of fabrication due to a single-layer metamaterial, scaling up an existing design rather than scaling down, and ease of integration with existing focalplane array microbolometers.
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 149.99K | Year: 2015
ABSTRACT:We propose to design, develop, and demonstrate a metasurface-enhanced hyperspectral filter suitable for imaging spectrometry applications. The filter is part of a two-stage solution that integrates a patterned micro-antenna metasurface along with a DBR resonant cavity filter capable of creating an extremely narrow-band spectral response. By combining the two spectral filters into one, the out-of-band mode suppression is greatly improved allowing for a broader range of operation. Material alteration in the filter leads to multiple variations in the filter design, which allows for spectral operation ranging from visible to infrared. Fabrication of the filter can be realized through micro-photolithography fabrication process using standard optical materials. Compared to currently available technology, the proposed design provides size, weight, power (SWaP) advantage over existing systems that utilize bulky, external optical components to achieve similar performance. The filter design will be optimized for fast f/# systems and made highly compatible with FPAs. Integration of the filter can be achieved by placement into the line of sight or mounted onto the detector to create a compact detecting solution. Applications using this filter range from hyperspectral sensing at longer ranges than current systems, as well as lower cost sensors for agriculture, object recognition, and homeland security.BENEFIT:We expect the design and fabrication of the proposed effort to result in a metasurface-enhanced hyperspectral pixelated filter for use with standard focal plane arrays (FPAs). Using a two-stage light controlling process, the filter is expected to provide narrower line widths under a fast f/# optical system and be highly scalable for operation at various spectral bands. As a result, the filter will be capable of providing a broader range of operation when compared to the current generation of hyperspectral filters. The fabrication of the proposed filter will be performed using a standard photolithography process, which will result in a compact device that is easily integrated with detectors through a growth or bonding process. Compared to similarly performing hyperspectral filters, this approach is expected to produce a size, weight, and power (SWaP) advantage due to omitting certain bulky optical components. The expected hyperspectral pixelated filter will target both the defense and commercial markets, particularly focusing on object detection, surveillance, remote sensing, defect identification, and chemical imaging.
Agency: Department of Defense | Branch: Missile Defense Agency | Program: STTR | Phase: Phase II | Award Amount: 750.00K | Year: 2010
The proposed project will develop three actively configurable metamaterial of relevance to both i) MDA’s high-priority and near-term need for stray light testing and diagnosis and ii) the interceptor functions of THAAD, Ascent Phase Interceptors, MKV and Space Systems. Phoebus’s configurable metamaterials aperture arrays will consist of single-layer metallic thin films patterned with light-channeling subwavelength sized dielectric apertures. All structures will tap into the metamaterial phenomenon of anomalous optical transmission (AOT) through subwavelength sized apertures, that allow almost 100% of an incident beam to be transmitted through the structures. The apertures will be filled with electro-optical materials that exhibit tuning of their dielectric constants when a voltage is applied, hence tuning of the transmissive/reflectance properties as well. Two of the devices will be actively configurable apertures that will be will be integrated into the stray light detection system being developed by Phase I awardee, Opt-E. The third device is a light harvesting, tunable, wavelength selective transmitting/lensing metamaterial that can be switch between the transmission and lensing of MWIR and LWIR spectral bands. Phoebus has developed a realizable commercialization plan to exploit profitable markets for sensor systems, advanced optical components, polarimetric sensing and renewable energy devices using its patent-pending metamaterials.
Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase I | Award Amount: 99.97K | Year: 2013
We propose a meta-surface consisting of a periodic array of metal-like patches that will allow focusing and steering a radiation beam in the millimeter frequency range. The direction of the beam will be controlled by controlling the phase change acquired by the beam as it is transmitted through this metasurface. The phase change at the surface is controlled by the shape and capacitance of metallic features on the surface. Two approaches will be investigated that will allow for active tuning of the steering. One approach will be to actively tune with an applied electrical bias using varactors and transmitarrays, the second approach will use a type of"dynamic lithography"that produces electric charge concentrations on surfaces that act as metal structures and that is fully tunable in an active way. The proposed structures will allow for miniaturization to reduce the form factor to allow for a hand-held device, and will eliminate detuning effects due to temperature fluctuations in the device.
Agency: Department of Defense | Branch: Office for Chemical and Biological Defense | Program: SBIR | Phase: Phase I | Award Amount: 99.98K | Year: 2014
We aim to create a low-cost, high-sensitivity hand-held plasmonic biosensor capable of sensing biotoxins. We will do this by using newly developed biodesign technology to create a new class of proteins which have an orders-of-magnitude increase in SPR signal-to-noise. These will be incorporated into a novel SPR device in which the transmission of light is affected by the binding of a particular toxin to the functionalized surface. Such a system will be inherently more robust and compact because all the optical components are in line with each other. These will be used in a transmission based"tricorder"device with an easily replicable disposable sensing chip.
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 149.80K | Year: 2013
We propose a two-layer anti-reflective coating (ARC) that will have omni-directional properties. This coating will guide the light that is incident from oblique angles and orient it to become perpendicular to the solar cell surface. The top-most part of the coating will have a graded index of refraction, starting from an index of 1 at the air interface and gradually increasing to an index of about 1.5 at the interface between the two coating layers. This top layer will be made out of cheap polymer that can be deposited by dip-coating, and the graded index will be achieved by texturing the polymer to have up-right pyramids. As the light travels through this layer, it will bend to become perpendicular to the surface of constant index regardless of initial angle of incidence. The bottom layer of our proposed coating will consist of a standard silicon nitride (SiN) thin film layer that will act as an interference ARC between the polymer and the silicon surface of the solar cell to minimize reflections between each layer. We believe this approach offers cost and weight advantages over not only current mechanical solar directing systems, but also other similar graded ARCs based on silicon oxide.
Agency: Department of Defense | Branch: Office for Chemical and Biological Defense | Program: SBIR | Phase: Phase II | Award Amount: 497.98K | Year: 2013
We will continue developing a plasmonic metamaterial with strong absorption within a narrow band that is dynamically tunable over the 8-10 micron range. A metamaterial consisting of one or more bi-layers of thin metal and dielectric films will trap, concentrate and absorb a narrow frequency band while strongly reflecting out-of-band light. Tuning the frequency of the absorption band may be achieved either by MEMS actuation to change geometry, or by carrier density modulation to change the refractive index of semiconductor layers. The metamaterial may be fabricated with standard lithography techniques and processes that are compatible with microbolometer manufacturing. We believe that this plasmonic perfect absorber approach offers considerable advantages over a coupled split-ring and cut wire approach that is being pursued by other groups, because the material losses in real metals will always broaden out a resonance that relies on current loops in metals. By completion of Phase II, we will have evaluated a fully integrated plasmonic absorber microbolometer system for detecting chemical and biological agents.
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 79.66K | Year: 2015
The proposed project involves the integration of an Artificial Magnetic Materials (AMMs) with a planar antenna system with the system exhibiting multiple RFI mitigation features. The system will protect against spatial RFI by using a metamaterial surface to reduce the beamwidth of the radiation pattern. The antenna systems will be designed as an array of supercells consisting of the radiating element and the metamaterial reflector. Cells would be configured using a butler matrix and create a focused beam which would further reduce spatial RFI. The proposed technology will provides a Size, Weight, and Power (SWaP) advantage over SATCOM antenna systems currently deployed in CUBESATs. The applications for this technology are focused for CUBESATs and satellite-based communication systems.