摘要:
A waveguide intersection includes an input waveguide and an output waveguide; a crossing waveguide intersecting the input waveguide and the output waveguide to form an intersection; and a block that is optically joined to the intersection such that a guided mode is produced within the intersection. A method of reducing optical losses within a waveguide intersection includes increasing a cross-sectional height of an intersection such that optical energy passing through the intersection is laterally confined.
摘要:
An emissions control system for a vehicle having an exhaust system with an exhaust gas conduit and a catalytic converter configured to receive exhaust gas from an engine is provided. In one example implementation, the system includes an engine controller configured to control the engine to adjust an air to fuel ratio (lambda) thereof. The engine controller is configured to operate the engine with at least one of the following lambda control strategies (i) a first control strategy comprising operating at a first reference lambda modified by a first percent kick, and a first rich lambda lag time shorter than a first lean lambda lag time, and (ii) a second control strategy comprising operating at a second reference lambda modified by a second percent kick, and a second rich lag time longer than a second lean lambda lag time, to thereby simultaneously meet predetermined NOx and CO emissions targets.
摘要:
A surface enhanced Raman spectroscopy (SERS) apparatus, system and method employ a plurality of nanorods configured to vibrate. The apparatus includes the nanorods having tips at free ends opposite an end attached to a substrate. The tips are configured to adsorb an analyte and to vibrate at a vibration frequency. The apparatus further includes a vibration source configured to vibrate the free ends of the nanorods at the vibration frequency in a back-and-forth motion. Vibration of the nanorods is configured to facilitate detection of a Raman scattering signal emitted by the analyte adsorbed on the nanorod tips. The system further includes a synchronous detector configured to receive the Raman signal and to be gated cooperatively with the vibration of the nanorods. The method includes inducing a vibration of the nanorods, illuminating the vibrating tips to produce a Raman signal, and detecting the Raman signal using the detector.
摘要:
An apparatus for detecting at least one species using Raman light detection includes at least one laser source for illuminating a sample containing the at least one species. The apparatus also includes a modulating element for modulating a spatial relationship between the sample and the light beams to cause relative positions of the sample and the light beams to be oscillated, in which Raman light at differing intensity levels are configured to be emitted from the at least one species based upon the different wavelengths of the light beams illuminating the sample. The apparatus also includes a Raman light detector and a post-signal processing unit configured to detect the at least one species.
摘要:
An analyzer is disclosed herein. The analyzer encompasses a substrate having a surface with a plurality of distinct V-grooves formed therein. An input flow channel is configured to intersect and fluidly communicate with each of the plurality of distinct V-grooves at respective input points, and an output flow channel is configured to intersect and fluidly communicate with each of the plurality of distinct V-grooves at respective output points.
摘要:
An apparatus for detecting at least one molecule using Raman light detection includes a substrate for supporting a sample containing the at least one molecule, a laser source for emitting a laser beam to cause Raman light emission from the at least one molecule, a modulating element for modulating a spatial relationship between the laser beam and the substrate at an identified frequency to cause the Raman light to be emitted from the at least one molecule at the identified frequency, at least one detector for detecting the Raman light emitted from the at least one molecule, and a post-signal processing unit configured to process the detected Raman light emission at the identified frequency to detect the at least one molecule.
摘要:
A type and polarization selective device for Raman spectroscopy includes a set of at least two antennas and a gap at their intersection. First antenna geometry is such that it is configured to resonate, for first or second (different from the first) polarization, at a predetermined stimulation frequency of a material for which Raman scattering is to be studied, or at a Stokes or anti-Stokes frequency corresponding with the material when excited at stimulation frequency. Second antenna geometry is such that it is configured to resonate, for the other of second or first polarization, at the Stokes frequency when the first antenna is configured to resonate at the stimulation or anti-Stokes frequency, or at the anti-Stokes frequency when the first antenna is configured to resonate at the stimulation or Stokes frequency, or at the stimulation frequency when the first antenna is configured to resonate at the Stokes or anti-Stokes frequency.
摘要:
Various embodiments of the present invention are directed to external, electronically controllable, negative index material-based modulators. In one aspect, an external modulator comprises a negative index material in electronic communication with an electronic signal source. The negative index material receives an electronic signal encoding data from the electronic signal source and an unmodulated carrier wave from an electromagnetic radiation source. Magnitude variations in the electronic signal produce corresponding effective refractive index changes in the negative index material encoding the data in the amplitude and/or phase of the carrier wave to produce an electromagnetic signal.
摘要:
Various embodiments of the present invention are directed to compact, sub-wavelength optical resonators. In one aspect, an optical resonator comprises two approximately parallel reflective structures positioned and configured to form a resonant cavity. The resonator also includes a fishnet structure disposed within the cavity and oriented approximately parallel to the reflective structures. The resonant cavity is configured with a cavity length that can support resonance with electromagnetic radiation having a fundamental wavelength that is more than twice the cavity length.
摘要:
An apparatus for detecting at least one species using Raman light detection includes at least one laser source for illuminating a sample containing the at least one species. The apparatus also includes a modulating element for modulating a spatial relationship between the sample and the light beams to cause relative positions of the sample and the light beams to be oscillated, in which Raman light at differing intensity levels are configured to be emitted from the at least one species based upon the different wavelengths of the light beams illuminating the sample. The apparatus also includes a Raman light detector and a post-signal processing unit configured to detect the at least one species.