Abstract: A non-volatile logic gate, including a magnetic material having a shape induced magnetic anisotropy, wherein a shape of the magnetic material has a first vertex, a second vertex, and a third vertex and supports a single magnetic domain; regions of the magnetic material including a first input region adjacent the first vertex, a second input region adjacent the second vertex, and an output region adjacent a third vertex; the first input region for receiving a first logic input to the logic gate, the second input region for receiving a second logic input to the logic gate, and the output region for outputting at least one logic output of the logic gate; and the shape induced magnetic anisotropy determining at least part of a truth table for the logic gate, so that the logic gate produces the at least one logic output from the logic inputs using the shape.

Abstract: A direct detector for terahertz radiation comprises a grating-gated field-effect transistor with one or more quantum wells that provide a two-dimensional electron gas in the channel region. The grating gate can be a split-grating gate having at least one finger that can be individually biased. Biasing an individual finger of the split-grating gate to near pinch-off greatly increases the detector's resonant response magnitude over prior QW FET detectors while maintaining frequency selectivity. The split-grating-gated QW FET shows a tunable resonant plasmon response to FIR radiation that makes possible an electrically sweepable spectrometer-on-a-chip with no moving mechanical optical parts. Further, the narrow spectral response and signal-to-noise are adequate for use of the split-grating-gated QW FET in a passive, multispectral terahertz imaging system. The detector can be operated in a photoconductive or a photovoltaic mode.

Abstract: A terahertz radiation mixer comprises a heterodyned field-effect transistor (FET) having a high electron mobility heterostructure that provides a gatable two-dimensional electron gas in the channel region of the FET. The mixer can operate in either a broadband pinch-off mode or a narrowband resonant plasmon mode by changing a grating gate bias of the FET. The mixer can beat an RF signal frequency against a local oscillator frequency to generate an intermediate frequency difference signal in the microwave region. The mixer can have a low local oscillator power requirement and a large intermediate frequency bandwidth. The terahertz radiation mixer is particularly useful for terahertz applications requiring high resolution.