摘要:
A sub-wavelength grating device having controlled phase response includes a grating layer having line widths, line thicknesses, line periods, and line spacings selected to produce a first level of control in phase changes of different portions of a beam of light reflected from the grating layer. The device also includes a substrate affixed to the grating layer that produces a second level of control in phase changes of different portions of a beam of light reflected from the grating layer, the second level of control being accomplished abrupt stepping of the substrate in a horizontal dimension, ramping the substrate in a horizontal dimension, or changing the index of refraction in a horizontal dimension.
摘要:
A sub-wavelength grating device having controlled phase response includes a grating layer having line widths, line thicknesses, line periods, and line spacings selected to produce a first level of control in phase changes of different portions of a beam of light reflected from the grating layer. The device also includes a substrate affixed to the grating layer that produces a second level of control in phase changes of different portions of a beam of light reflected from the grating layer, the second level of control being accomplished abrupt stepping of the substrate in a horizontal dimension, ramping the substrate in a horizontal dimension, or changing the index of refraction in a horizontal dimension.
摘要:
Raman systems include a radiation source, a radiation detector, and a Raman device or signal-enhancing structure. Raman devices include a tunable resonant cavity and a Raman signal-enhancing structure coupled to the cavity. The cavity includes a first reflective member, a second reflective member, and an electro-optic material disposed between the reflective members. The electro-optic material exhibits a refractive index that varies in response to an applied electrical field. Raman signal-enhancing structures include a substantially planar layer of Raman signal-enhancing material having a major surface, a support structure extending from the major surface, and a substantially planar member comprising a Raman signal-enhancing material disposed on an end of the support structure opposite the layer of Raman signal-enhancing material. The support structure separates at least a portion of the planar member from the layer of Raman signal-enhancing material by a selected distance of less than about fifty nanometers.
摘要:
A negative index material (or metamaterial) crossbar includes a first layer of approximately parallel nanowires and a second layer of approximately parallel nanowires that overlay the nanowires in the first layer. The nanowires in the first layer are approximately perpendicular in orientation to the nanowires in the second layer. Each nanowire of the first layer and each nanowire of the second layer has substantially regularly spaced fingers. The crossbar further includes resonant elements at nanowire intersections between the respective layers. Each resonant element includes two fingers of a nanowire in the first layer and two fingers of a nanowire in the second layer.
摘要:
Various embodiments of the present invention relate to systems that can be used as holograms and can be electronically controlled and dynamically reconfigured to generate three-dimensional motion picture images. In one embodiment, a dynamically reconfigurable hologram (1200) comprises a phase-control layer (1202) including a two-dimensional array of phase-modulation pixels (1212). The hologram also comprises an intensity-control layer (1204) including a two-dimensional array of intensity-control pixels (1214). One or more three-dimensional motion pictures can be produced by electronically addressing the individual phase-modulation pixels and intensity-control pixels in order to phase and control the intensity of light emanating from pixels of the hologram.
摘要:
Various embodiments of the present invention are directed to external, electronically controllable modulators. In one embodiment, a modulating device (100,400) includes a first electrode (104,404), a second electrode (106,406), and an active region (102,402). The active region is configured so that at least a portion of the active region is disposed between the first electrode and the second electrode. Applying a voltage of an appropriate magnitude and polarity to the electrodes changes the conductivity of the active region which in turn shifts the phase and/or amplitude of electromagnetic radiation transmitted through the active region.
摘要:
A sensing device includes an optical cavity having two substantially opposed reflective surfaces. At least one nanowire is operatively disposed in the optical cavity. A plurality of metal nanoparticles is established on the at least one nanowire.
摘要:
A configurable memristive device (300) for regulating an electrical signal includes a memristive matrix (350) containing a first dopant species; emitter (320), collector (310), and a base electrodes (330, 340) which are in contact with the memristive matrix (350); and a mobile dopant species contained within a central region (360) contiguous with the base electrodes (330, 340), the mobile dopant species moving within the memristive matrix (350) in response to a programming electrical field. A method of configuring and using a memristive device (300) includes: applying a programming electrical field across a memristive matrix (350) such that a mobile dopant species creates a central doped region (360) which bisects the memristive matrix (350); and applying a control voltage to the central doped region (360) to regulate current flow between an emitter electrode (320) and a collector electrode (310).
摘要:
Self-organized, or self-assembled, nanowires of a first composition may be used as an etching mask for fabrication of nanowires of a second composition. The method for forming such nanowires comprises: (a) providing an etchable layer of the second composition and having a buried insulating layer beneath a major surface thereof; (b) growing self-assembled nanowires on the surface of the etchable layer; and (c) etching the etchable layer anisotropically down to the insulating layer, using the self-assembled nanowires as a mask. The self-assembled nanowires may be removed or left. In either event, nanowires of the second composition are formed. The method enables the formation of one-dimensional crystalline nanowires with widths and heights at the nanometer scale, and lengths at the micrometer scale, which are aligned along certain crystallographic directions with high crystal quality. Further, the method of the present invention avoids traditional lithography methods, minimizes environmental toxic chemicals usage, simplifies the manufacturing processes, and allows the formation of high-quality one-dimensional nanowires over large areas.
摘要:
A thermoelectric device having a variable cross-section connecting structure includes a first electrode, a second electrode, and a connecting structure connecting the first electrode and the second electrode. The connecting structure has a first section and a second section. The width of the second section is greater than the width of the first section, and the width of the first section is less than a width that is approximately equivalent to a phonon mean free path through the first section.