Abstract: The present invention provides methods for purifying a layer of carbon nanotubes comprising providing a precursor layer of substantially aligned carbon nanotubes supported by a substrate, wherein the precursor layer comprises a mixture of first carbon nanotubes and second carbon nanotubes; selectively heating the first carbon nanotubes; and separating the first carbon nanotubes from the second carbon nanotubes, thereby generating a purified layer of carbon nanotubes. Devices benefiting from enhanced electrical properties enabled by the purified layer of carbon nanotubes are also described.

Abstract: The present invention provides methods for purifying a layer of carbon nanotubes comprising providing a precursor layer of substantially aligned carbon nanotubes supported by a substrate, wherein the precursor layer comprises a mixture of first carbon nanotubes and second carbon nanotubes; selectively heating the first carbon nanotubes; and separating the first carbon nanotubes from the second carbon nanotubes, thereby generating a purified layer of carbon nanotubes. Devices benefiting from enhanced electrical properties enabled by the purified layer of carbon nanotubes are also described.

Abstract: A Raman detecting system for detecting a vapor of an explosive includes a surface-enhanced Raman scattering substrate for absorbing the vapor of the explosive. The substrate includes a carbon nanotube film structure and a plurality of metallic particles disposed on the carbon nanotube film structure. The carbon nanotube film structure includes a plurality of stacked carbon nanotube films.

Abstract: A method of analyzing a remotely-located object includes the step of illuminating at least a portion of a targeted object with electromagnetic radiation to induce a phase transformation in the targeted object, wherein the phase transformation produces an emitter plasma, which emits terahertz radiation. The method also includes the step of ionizing a volume of an ambient gas to produce a sensor plasma by focusing an optical probe beam in the volume and the step of detecting an optical component of resultant radiation produced from an interaction of the focused optical probe beam and the terahertz radiation in the sensor plasma. Detecting an optical component of the resultant radiation emitted by the sensor plasma facilitates detection of a characteristic fingerprint of the targeted object imposed onto the terahertz radiation produced as a result of the induced phase transformation.

Abstract: A Raman detecting system for detecting a vapor of an explosive includes a surface-enhanced Raman scattering substrate for absorbing the vapor of the explosive. The substrate includes a carbon nanotube film structure and a plurality of metallic particles disposed on the carbon nanotube film structure. The carbon nanotube film structure includes a plurality of stacked carbon nanotube films.

Abstract: A method of analyzing a remotely-located object includes the step of illuminating at least a portion of a targeted object with electromagnetic radiation to induce a phase transformation in the targeted object, wherein the phase transformation produces an emitter plasma, which emits terahertz radiation. The method also includes the step of ionizing a volume of an ambient gas to produce a sensor plasma by focusing an optical probe beam in the volume and the step of detecting an optical component of resultant radiation produced from an interaction of the focused optical probe beam and the terahertz radiation in the sensor plasma. Detecting an optical component of the resultant radiation emitted by the sensor plasma facilitates detection of a characteristic fingerprint of the targeted object imposed onto the terahertz radiation produced as a result of the induced phase transformation.

Abstract: A method for generating amplified terahertz radiation includes inducing a first volume of a gas to produce a seed plasma and emit pulsed seed terahertz radiation by focusing an optical seed beam in the first volume. The seed terahertz radiation is then amplified by focusing an optical gain beam to produce a gain plasma in a second volume overlapping with the pulsed seed terahertz radiation remote from the seed plasma. The method may be implemented in a system for detecting and analyzing a remotely-located object such as an explosive material, a biological agent, and a chemical agent.

Abstract: A method of analyzing a remotely-located object includes the step of illuminating at least a portion of a targeted object with electromagnetic radiation to induce a phase transformation in the targeted object, wherein the phase transformation produces an emitter plasma, which emits terahertz radiation. The method also includes the step of ionizing a volume of an ambient gas to produce a sensor plasma by focusing an optical probe beam in the volume and the step of detecting an optical component of resultant radiation produced from an interaction of the focused optical probe beam and the terahertz radiation in the sensor plasma. Detecting an optical component of the resultant radiation emitted by the sensor plasma facilitates detection of a characteristic fingerprint of the targeted object imposed onto the terahertz radiation produced as a result of the induced phase transformation.

Abstract: A method for generating terahertz radiation includes inducing a background plasma in a volume of a gas by focusing a first optical beam in the volume, and generating pulsed terahertz radiation with enhanced generation efficiency by focusing a second time-delayed optical beam in the background plasma. The method may be implemented in a system for detecting and analyzing a remotely-located object.

Abstract: A method of analyzing a remotely-located object includes the steps of inducing a volume of an ionized ambient gas to emit pulsed terahertz radiation directed toward a targeted object by focusing an optical pump beam in the volume and ionizing another volume of the ambient gas to produce a sensor plasma by focusing an optical probe beam in the other volume of ambient gas. The interaction, in the sensor plasma, of the focused optical probe beam and an incident terahertz wave, which is produced by the targeted object reflecting, scattering, or transmitting the pulsed terahertz radiation, produces a resultant radiation. Detecting an optical component of the resultant radiation emitted by the sensor plasma facilitates detection of a signature of the targeted object imposed onto the incident terahertz radiation.

Abstract: A method of analyzing a remotely-located object includes the step of illuminating at least a portion of a targeted object with electromagnetic radiation to induce a phase transformation in the targeted object, wherein the phase transformation produces an emitter plasma, which emits terahertz radiation. The method also includes the step of ionizing a volume of an ambient gas to produce a sensor plasma by focusing an optical probe beam in the volume and the step of detecting an optical component of resultant radiation produced from an interaction of the focused optical probe beam and the terahertz radiation in the sensor plasma. Detecting an optical component of the resultant radiation emitted by the sensor plasma facilitates detection of a characteristic fingerprint of the targeted object imposed onto the terahertz radiation produced as a result of the induced phase transformation.

Abstract: A method for generating amplified terahertz radiation includes inducing a first volume of a gas to produce a seed plasma and emit pulsed seed terahertz radiation by focusing an optical seed beam in the first volume. The seed terahertz radiation is then amplified by focusing an optical gain beam to produce a gain plasma in a second volume overlapping with the pulsed seed terahertz radiation remote from the seed plasma. The method may be implemented in a system for detecting and analyzing a remotely-located object such as an explosive material, a biological agent, and a chemical agent.

Abstract: A method for generating terahertz radiation includes inducing a background plasma in a volume of a gas by focusing a first optical beam in the volume, and generating pulsed terahertz radiation with enhanced generation efficiency by focusing a second time-delayed optical beam in the background plasma. The method may be implemented in a system for detecting and analyzing a remotely-located object.

Abstract: A method of analyzing a remotely-located object includes the steps of inducing a volume of an ionized ambient gas to emit pulsed terahertz radiation directed toward a targeted object by focusing an optical pump beam in the volume and ionizing another volume of the ambient gas to produce a sensor plasma by focusing an optical probe beam in the other volume of ambient gas. The interaction, in the sensor plasma, of the focused optical probe beam and an incident terahertz wave, which is produced by the targeted object reflecting, scattering, or transmitting the pulsed terahertz radiation, produces a resultant radiation. Detecting an optical component of the resultant radiation emitted by the sensor plasma facilitates detection of a signature of the targeted object imposed onto the incident terahertz radiation.