Integrated terahertz frequency generator

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Terahertz radiation, in the range of 100 GHz to 30 THz, has been investigated for astronomy and analytical science. Recent advancements in photonics and nanotechnology are now enabling innovative research of new THz generation technologies. One technique for terahertz radiation is to use heterodyne photomixing by two lights of around ~0.8-micron incident on a low temperature grown GaAs photomixer. Another technique is to use quantum cascade lasers to obtain THz radiation with no frequency tunability and working at low temperature, and more cascade lasers are required with the decrease of THz. The third technique is to use a femto second laser within an optical bench with low output average power. Photonic technologies at 1.55 micron have been well established and explored for information and telecommunication sector. We will investigate and develop an integrated terahertz frequency generator by heterodyne photomixing of two lights at around 1.55-micron to obtain THz radiation from 100 GHz to 6 THz. The generator is composed of a dual-mode and tunable quantum-dot phase-locked semiconductor laser at around 1.55 micron, a high-power quantum-dot semiconductor amplifier, an ultrafast photomixer (low-temperature grown InGaAs) and a THz antenna. This THz generator will be cost-effective, robust, very compact, and integrated. The THz generator can be used for both sensing and communications. The applications include (1) detection of biological, medical and pharmaceutical science including biomolecules, medicines, cancer tissue, DNA, drug, proteins and bacteria, (2) semiconductor and other industrial applications including material evaluations, inspection of silicon solar cells, nanocomposites, polyfilms and dielectric films and fault analysis, (3) security screening including identifying signature of every explosive and narcotic, (4) information and communication technology including indoor and outdoor high speed wireless communications with possible 10 Gb/s in the future, (5) earth and space science including pollution analysis and observation, and gas sensing, and (6) basic science including food quality control.