Abstract: Provided are methods for imprinting a porous material, the methods including applying a first stamp to a porous material having an average pore size of less than about 100 ?m, the first stamp having at least a first portion having a first height, a second portion having a second height and a third portion having a third height, wherein the first height, second height and third height are different.

Abstract: Provided are patterned nanoporous gold (“P-NPG”) films that may act as at least one of an effective and stable surface-enhanced Raman scattering (“SERS”) substrate. Methods of fabricating the P-NPG films using a low-cost stamping technique are also provided. The P-NPG films may provide uniform SERS signal intensity and SERS signal intensity enhancement by a factor of at least about 1×107 relative to the SERS signal intensity from a non-enhancing surface.

Abstract: Provided are methods of patterning porous materials on the micro- and nanometer scale using a direct imprinting technique. The present methods of direct imprinting of porous substrates (“DIPS”), can utilize reusable stamps that may be directly applied to an underlying porous material to selectively, mechanically deform and/or crush particular regions of the porous material, creating a desired structure. The process can be performed in a matter of seconds, at room temperature or higher temperatures, and eliminates the requirement for intermediate masking materials and etching chemistries.

Abstract: Various embodiments of a composite material are provided. In one embodiment of the present invention a nanometer-scale composite material comprises, by volume, from about 1% to about 99% variable-conductivity material and from about 99% to about 1% conductive material. The composite material exhibits memristive properties when a voltage differential is applied to the nanocomposite. In another embodiment, a variable resistor device includes a first electrode terminal and a second electrode terminal and a nanocomposite in electrical communication with the electrode terminals. The composite material comprises, by volume, from about 1% to about 99% variable-conductivity material and from about 99% to about 1% conductive material. The memristor is tunable as the minimum instantaneous resistance can be altered several orders of magnitude by varying the composition and ratio of the variable-conductivity material and conductive material constituents of the composites.

Abstract: A sensor for sensing at least one biological target or chemical target is provided. The sensor includes a membrane includes a membrane material that supports generation and propagation of at least one waveguide mode, where the membrane material includes a plurality of voids having an average size <2 microns. The sensor also includes at least one receptor having structure for binding to the target within the plurality of voids, and an optical coupler for coupling light to the membrane sufficient to generate the waveguide mode in the membrane from photons incident on the optical coupler.

Abstract: Provided are methods for imprinting a porous material, the methods including applying a first stamp to a porous material having an average pore size of less than about 100 ?m, the first stamp having at least a first portion having a first height, a second portion having a second height and a third portion having a third height, wherein the first height, second height and third height are different.

Abstract: Various embodiments of a composite material are provided. In one embodiment of the present invention a nanometer-scale composite material comprises, by volume, from about 1% to about 99% variable-conductivity material and from about 99% to about 1% conductive material. The composite material exhibits memristive properties when a voltage differential is applied to the nanocomposite. In another embodiment, a variable resistor device includes a first electrode terminal and a second electrode terminal and a nanocomposite in electrical communication with the electrode terminals. The composite material comprises, by volume, from about 1% to about 99% variable-conductivity material and from about 99% to about 1% conductive material. The memristor is tunable as the minimum instantaneous resistance can be altered several orders of magnitude by varying the composition and ratio of the variable-conductivity material and conductive material constituents of the composites.

Abstract: A sensor for sensing at least one biological target or chemical target is provided. The sensor includes a membrane includes a membrane material that supports generation and propagation of at least one waveguide mode, where the membrane material includes a plurality of voids having an average size <2 microns. The sensor also includes at least one receptor having structure for binding to the target within the plurality of voids, and an optical coupler for coupling light to the membrane sufficient to generate the waveguide mode in the membrane from photons incident on the optical coupler.

Abstract: A sensor for sensing at least one biological target or chemical target is provided. The sensor includes a membrane includes a membrane material that supports generation and propagation of at least one waveguide mode, where the membrane material includes a plurality of voids having an average size<2 microns. The sensor also includes at least one receptor having structure for binding to the target within the plurality of voids, and an optical coupler for coupling light to the membrane sufficient to generate the waveguide mode in the membrane from photons incident on the optical coupler.

Abstract: Provided are patterned nanoporous gold (“P-NPG”) films that may act as at least one of an effective and stable surface-enhanced Raman scattering (“SERS”) substrate. Methods of fabricating the P-NPG films using a low-cost stamping technique are also provided. The P-NPG films may provide uniform SERS signal intensity and SERS signal intensity enhancement by a factor of at least about 1×107 relative to the SERS signal intensity from a non-enhancing surface.

Abstract: Diffraction gratings comprising a substrate with protrusions extending therefrom. In one embodiment, the protrusions are made of a porous material, for example porous silicon with a porosity of greater than about 10%. The diffraction grating may also be constructed from multiple layers of porous material, for example porous silicon with a porosity of greater than about 10%, with protrusion of attached thereto. In some embodiments the protrusions may be made from photoresist or another polymeric material. The gratings are the basis for sensitive sensors. In some embodiments, the sensors are functionalized with selective binding species, to produce sensors that specifically bind to target molecules, for example chemical or biological species of interest.

Abstract: Provided are methods of patterning porous materials on the micro- and nanometer scale using a direct imprinting technique. The present methods of direct imprinting of porous substrates (“DIPS”), can utilize reusable stamps that may be directly applied to an underlying porous material to selectively, mechanically deform and/or crush particular regions of the porous material, creating a desired structure. The process can be performed in a matter of seconds, at room temperature or higher temperatures, and eliminates the requirement for intermediate masking materials and etching chemistries.

Abstract: Diffraction gratings comprising a substrate with protrusions extending therefrom. In one embodiment, the protrusions are made of a porous material, for example porous silicon with a porosity of greater than about 10%. The diffraction grating may also be constructed from multiple layers of porous material, for example porous silicon with a porosity of greater than about 10%, with protrusion of attached thereto. In some embodiments the protrusions may be made from photoresist or another polymeric material. The gratings are the basis for sensitive sensors. In some embodiments, the sensors are functionalized with selective binding species, to produce sensors that specifically bind to target molecules, for example chemical or biological species of interest.

Abstract: A sensor for sensing at least one biological target or chemical target is provided. The sensor includes a membrane includes a membrane material that supports generation and propagation of at least one waveguide mode, where the membrane material includes a plurality of voids having an average size<2 microns. The sensor also includes at least one receptor having structure for binding to the target within the plurality of voids, and an optical coupler for coupling light to the membrane sufficient to generate the waveguide mode in the membrane from photons incident on the optical coupler.

Abstract: We have developed a simple method to locally change the optical properties of porous silicon multilayers and photonic crystal architectures. This technique allows for the direct photolithography of porous silicon multilayers, heterostructures, and photonic crystals. The procedure controls the local oxidation within the porous silicon layers via ultraviolet radiation or via high intensity laser beam (?=532.8 nm) exposure. Subsequently, immersion of the non-irradiated and irradiated regions of the porous silicon heterostructures within an alcohol solvent (for example, methanol and ethanol) induces either a marked degradation or no degradation, respectively, in the optical properties of the material. This direct, optical lithographic technique may have significant use in the production of silicon-based optical and opto-electronic devices for laser, optical computation, telecommunications, and other applications.

Abstract: A method for controlling one or more temperature dependent optical properties of a structure in accordance with embodiments of the present invention includes heating at least a portion of a photonic band-gap structure and oxidizing the portion of the photonic band-gap structure during the heating to alter at least one temperature dependent optical property of the stack.