Abstract: Optical tweezer methods and apparatus that operate in reflection mode use polarization selection to isolate an input laser signal from optical signals associated with trapping. A trapping aperture or apertures can be defined in a conductive film such as a gold film have a polarization-dependent reflectance due to asymmetry of the aperture, and a reflected beam is polarized differently than an incident beam. Polarization of scattered light from the aperture can thus be distinguished from polarization of the incident beam. In some cases, an aperture is not used but instead polarizing nanoparticles, such as nanorods, are detected based on either transmitted or reflected optical radiation in a different state of polarization than that of the incident beam.

Abstract: Single molecule analysis of small proteins in aqueous environment without modifications (e.g., labels, tethers) elucidates their biophysics and interactions relevant to drug discovery. By fringe-field dielectrophoresis we demonstrate an order of magnitude speed up in nanoaperture optical tweezers for analyzing proteins below 5 kDa in solution, quantifying size and shape.

Abstract: Disclosed are systems and methods for improving applications involving the generation and detection of electromagnetic radiation at terahertz (THz) frequencies. Embodiments of the systems and methods include the fabrication and use of plasmonic devices that enhance light-matter interaction at the nanometer scale by extreme focusing with nanostructured metals. This plasmonic enhancement is used to produce high efficiency THz photoconductive switches that combine the benefits of low-temperature grown GaAs while using mature 1.55 ?m femtosecond lasers operating with photon energy below the GaAs band-gap.

Abstract: Optically trapped specimens (typically nanoparticles having diameters between 1 and 50 nm) are excited with an optical beam so as to induce vibrations in the specimens. A trapping optical beam and the excitation optical beam can produce vibrations based on a difference frequency based on the trapping optical beam and the excitation optical beam. Scattered optical radiation as a function of modulation frequency can be recorded and used to identify or characterize the specimen.

Abstract: A method for quantifying acetylamantadine in a urine sample comprises eluting acetylamantadine from the urine sample using solid phase extraction and quantifying the acetylamantadine eluted from the urine sample using Raman spectroscopy.

Abstract: Disclosed are systems and methods for improving applications involving the generation and detection of electromagnetic radiation at terahertz (THz) frequencies. Embodiments of the systems and methods include the fabrication and use of plasmonic devices that enhance light-matter interaction at the nanometer scale by extreme focusing with nanostructured metals. This plasmonic enhancement is used to produce high efficiency THz photoconductive switches that combine the benefits of low-temperature grown GaAs while using mature 1.55 ?m femtosecond lasers operating with photon energy below the GaAs band-gap.

Abstract: A method for quantifying acetylamantadine in a urine sample comprises eluting acetylamantadine from the urine sample using solid phase extraction and quantifying the acetylamantadine eluted from the urine sample using Raman spectroscopy.

Abstract: Molecules or particle having a hydrodynamic radius as small as 3.5 nm can be trapped using a double-nanohole structure defined in a metal film or other metallic layer. Application of a suitable optical radiation flux to the double-nanohole structure can provide a folding and/or binding of protein molecules that can be identified based on changes in optical transmission. Varying nanohole transmissions can thus be associated with trapping, binding and unfolding of biological particles. The double-nanohole defines cusps, but such cusps can be defined in other ways as well.

Abstract: The present invention presents a device and methods of use thereof in combined electrohydrodynamic concentration and plasmonic detection of a charged species of interest using a flow-through nanohole array. The device comprises microchannels, which are linked to a substrate with arrays of through nanoholes, wherein the substrate comprises two layers, wherein one of the layers is made of insulator material and one of the layers is made of metal, whereby induction of an electric field across the nanohole array results in the species of interest concentrating inside the nanoholes and in the vicinity of the nanohole arrays. The induction of an electric field is achieved by means of an external electric field source, which is applied to the fluid containing the species of interest, resulting in electroosmotic (EO) flow. An additional pressure driven fluid flow in the microchannels, co-directional to the EO flow is applied by external means.

Abstract: A method for quantifying acetylamantadine in a urine sample comprises eluting acetylamantadine from the urine sample using solid phase extraction and quantifying the acetylamantadine eluted from the urine sample using Raman spectroscopy.

Abstract: Optically trapped specimens (typically nanoparticles having diameters between 1 and 50 nm) are excited with an optical beam so as to induce vibrations in the specimens. A trapping optical beam and the excitation optical beam can produce vibrations based on a difference frequency based on the trapping optical beam and the excitation optical beam. Scattered optical radiation as a function of modulation frequency can be recorded and used to identify or characterize the specimen.

Abstract: Disclosed are devices and methods for enhancing the performance of photoconductive switches or photomixers used to generate or receive terahertz radiation. An interlaced electrode is used to minimize carrier transit times across an absorbing semiconductor photoconductor. This electrode is designed to support a plasmonic resonance such that coupling of the optical pump signal to the absorbing photoconductor is enhanced.

Abstract: Disclosed are devices and methods for enhancing the performance of photoconductive switches or photomixers used to generate or receive terahertz radiation. An interlaced electrode is used to minimize carrier transit times across an absorbing semiconductor photoconductor. This electrode is designed to support a plasmonic resonance such that coupling of the optical pump signal to the absorbing photoconductor is enhanced.

Abstract: Molecules or particle having a hydrodynamic radius as small as 3.5 nm can be trapped using a double-nanohole structure defined in a metal film or other metallic layer. Application of a suitable optical radiation flux to the double-nanohole structure can provide a folding and/or binding of protein molecules that can be identified based on changes in optical transmission. Varying nanohole transmissions can thus be associated with trapping, binding and unfolding of biological particles. The double-nanohole defines cusps, but such cusps can be defined in other ways as well.

Abstract: The present invention presents a device and methods of use thereof in combined electrohydrodynamic concentration and plasmonic detection of a charged species of interest using a flow-through nanohole array. The device comprises microchannels, which are linked to a substrate with arrays of through nanoholes, wherein the substrate comprises two layers, wherein one of the layers is made of insulator material and one of the layers is made of metal, whereby induction of an electric field across the nanohole array results in the species of interest concentrating inside the nanoholes and in the vicinity of the nanohole arrays. The induction of an electric field is achieved by means of an external electric field source, which is applied to the fluid containing the species of interest, resulting in electroosmotic (EO) flow. An additional pressure driven fluid flow in the microchannels, co-directional to the EO flow is applied by external means.