Abstract: A method for forming cathodes for use in field emission devices using nanoparticles, such as carbon nanotubes (CNTs), is disclosed. The CNT layer comprises the electron emitting material on the surface of the cathode. Using the methods of the present invention, the density of the deposited CNTs may be modulated by forming emitter islands on the surface of the cathode. The size and distribution of the CNT emitter islands serve to optimize the field emission properties of the resulting CNT layer. In one embodiment, the CNT emitter islands are formed using a screen-printing deposition method. The present invention may be practiced without further process steps after deposition which activate or align the carbon nanotubes for field emission.

Abstract: An optoelectronic modulator is based on the concentration of an electron beam from an electron gun by a tapered cavity, which sides are photosensitive and change the electrical conductivity under the illumination of light (electromagnetic radiation). The light modulation causes the corresponding changes in the current transported across the walls of the cavity. The remaining part of the electron current exits the cavity aperture and forms an amplitude-modulated divergent electron beam.

Abstract: Embodiments of the present invention are generally directed to the remote detection of explosives and other harmful materials. In some such embodiments, such remote detection involves the use of semiconducting nanoparticles. In some or other such embodiments, such remote detection involves the use of photoacoustic detection and/or spectroscopy. In some such latter embodiments, the photoacoustic system comprises a light source 201 that passes through a chopper 202 and into a photoacoustic cell 203 comprising the analyte gas. Pressure waves within the cell are detected as sound waves by microphones 204. The signal produced by the microphones can then be amplified and transmitted to a remote location, typically via a wireless means.

Abstract: A hydrogen sensor (100) with instant response that uses one or more quartz tuning forks (101, 102) while no chemical reactions or other material modifications are involved. Sensor (100) can be used in any application to measure percent range of hydrogen concentrations.