The present invention provides a terahertz oscillator utilizing a GaN Gunn diode. A terahertz wave is generated in the active layer of the Gunn diode fabricated on GaN substrate. A GaN substrate is designed to act as a waveguide of the terahertz wave. Since the waveguide and the Gunn diodes are integrated, the terahertz wave generated in the active layer couples well with the waveguide made of the GaN substrates. The terahertz wave is emitted from the edge of the waveguide efficiently. To ensure high-reliability through reduction of radiation loss and mitigation of electromigration of anode metal, a GaN substrate with low dislocation density is used. The dislocation density of the GaN substrate is less than 1×10.sup.6 cm.sup.−2. Particularly, usage of a GaN substrate made by the ammonothermal method is preferred.

The present invention discloses a neuron and a neuromorphic system including the same. The neuron according to an embodiment of the present invention includes a metal insulator metal (MIM) device including a metal ion-doped insulating layer and configured to perform integration and fire, and the MIM device is formed to have a negative differential resistance (NDR) region in which current decreases as voltage increases.

The lens unit includes a first lens array including a plurality of first lens elements each of which has a first optical axis and which are arranged in an arrangement direction perpendicular to the first optical axis. A second lens array includes a plurality of second lens elements each of which has a second optical axis and which are arranged in the arrangement direction while facing the first lens elements. The second lens array is in a positional relationship relative to the first lens array such that the second lens array is rotated about a virtual line perpendicular to both the first optical axis and the arrangement direction as the rotational axis by 180 degrees. The optical axes of the lens elements located at the substantially centers of the lens arrays in the arrangement direction are arranged to substantially coincide with each other.

The present invention provides a terahertz oscillator utilizing a GaN Gunn diode. A terahertz wave is generated in the active layer of the Gunn diode fabricated on GaN substrate. A GaN substrate is designed to act as a waveguide of the terahertz wave. Since the waveguide and the Gunn diodes are integrated, the terahertz wave generated in the active layer couples well with the waveguide made of the GaN substrates. The terahertz wave is emitted from the edge of the waveguide efficiently. To ensure high-reliability through reduction of radiation loss and mitigation of electromigration of anode metal, a GaN substrate with low dislocation density is used. The dislocation density of the GaN substrate is less than 1×10.sup.6 cm.sup.−2. Particularly, usage of a GaN substrate made by the ammonothermal method is preferred.

A composition of matter consisting primarily of a stabilizing element and a transition metal oxide, wherein the transition metal oxide is an anti-ferromagnetic Mott insulator with strong spin orbit interactions, and the composition of matter has a canted crystal structure.

A reservoir computing system comprising an input layer configured to receive input data from a signal propagation channel and to convert the input data into fixed input values, a reservoir configured to receive the fixed input values and generate a set of trained output values, and an output layer configured to receive the set of trained output values and generate a probability distribution based on the set of trained output values. The reservoir is comprised of a plurality of integrated oscillator components coupled in a fixed, random network, wherein each of the oscillator components is comprised of a device characterized by a current-voltage curve that comprises a region of non-linear behavior, such as a negative differential resistance (NDR) behavior.

A computing reservoir comprised of a plurality of oscillator components configured to receive input data and produce one or more output signals, and a feedback loop coupled to an output of the network, wherein the feedback loop is comprised of circuitry configured to establish and maintain an optimal operating point of the network based upon the output of the network.

The lens unit includes a first lens array including a plurality of first lens elements each of which has a first optical axis and which are arranged in an arrangement direction perpendicular to the first optical axis. A second lens array includes a plurality of second lens elements each of which has a second optical axis and which are arranged in the arrangement direction while facing the first lens elements. The second lens array is in a positional relationship relative to the first lens array such that the second lens array is rotated about a virtual line perpendicular to both the first optical axis and the arrangement direction as the rotational axis by 180 degrees. The optical axes of the lens elements located at the substantially centers of the lens arrays in the arrangement direction are arranged to substantially coincide with each other.

A vanadium dioxide (VO.sub.2)-based threshold switch device exhibiting current-controlled negative differential resistance (S-type NDR), an electrical oscillator circuit based on the threshold switch device, a wafer including a plurality of said devices, and a method of manufacturing said device are provided. The VO.sub.2-based threshold switch device exhibits volatile resistance switching and current-controlled negative differential resistance from the first time a sweeping voltage or voltage pulse is applied across the device without being treated with an electroforming process. Furthermore, the device exhibits substantially identical switching characteristics over at least 10.sup.3 switching operations between a high resistance state (HRS) and a low resistance state (LRS), and a plurality of threshold switch devices exhibits a threshold voltage V.sub.T spreading of less than about 25%. The threshold switch device may be included in an oscillator circuit to produce an astable oscillator that may serve as a functional building block in spiking-neuron based neuromorphic computing.

Examples herein relate to negative differential resistance devices. An example negative differential resistance device includes a first electrode and a first negative differential resistance device coupled to the first electrode. A second negative differential device is be coupled to the first negative differential resistance device. The second NDR device is different from the first NDR device. A second electrode is coupled to the second NDR device, and is electrically coupled with the first NDR device and the first electrode.