We report highly efficient continuous-wave terahertz (THz) photoconductive antenna based photomixer employing nano-gap electrodes in the active region. The tip-to-tip nano-gap electrode structure provides strong THz field enhancement and acts as a nano-antenna to radiate the THz wave generated in the active region of the photomixer. In addition, it provides good impedance matching to the THz pl...

Low-temperature-grown (LTG) GaAs is used as an optical-heterodyne converter or photomixer, to generate coherent continuous-wave (CW) output radiation at frequencies up to 5 THz. Photomixers consist of an epitaxial LTG-GaAs layer that is patterned with interdigitated metal electrodes, on which two laser beams are focused with their frequencies offset by the desired difference frequency. The diff...

An analysis has been carried out of optical heterodyne conversion with an interdigitated-electrode photomixer made from low-temperature-grown (LTG) GaAs and pumped by two continuous-wave, frequency-offset pump lasers. The analytic prediction is in excellent agreement with the experimental results obtained recently on a photomixer having 1.0~pm-wide electrodes and gaps. The analysis predicts tha...

Terahertz technology is a fast growing field with variety of applications in biology and medicine, medical imaging, material spectroscopy and sensing, monitoring and spectroscopy in pharmaceutical industry, security, and high-data-rate short-range communications. Among different terahertz sources, photomixers are potentially compact, low power consuming, coherent, low-cost, and tunable continuo...

The development of widely tunable coherent frequency sources for application as local oscillators or simply as test equipment above 1 THz remains an impediment in receiver development and characterization. Photomixer sources have demonstrated sufficient power to pump SIS mixers to over 600 GHz and have demonstrated over 2.5 THz of bandwidth in a single device. First generation photomixer system...

A low-temperature-grown GaAs interdigitated-electrode photomixer is used to generate coherent power at microwave frequencies. An output power of 200 PW ( 7 dBm) is generated by pumping the photomixer with two 70-mW modes of a Ti:Al,Qs laser, separated in frequency by 200 MHz. This represents an optical-to-microwave conversibn efficiency of 0.14%, which is within 50% of a prediction based on opt...

A novel terahertz plasma-wave photomixer that can improve the conversion gain and terahertz radiation power is proposed and evaluated. The photomixer is based on a high-electron mobility transistor and incorporates doubly interdigitated grating strips for the gate electrodes that periodically localize the 2D plasmons in 100-nm regions with a micron-order interval. A vertical cavity structure is...

We analytically investigated the feasibility of multiplier operation in the terahertz range for our original plasmon resonant photomixer. The photomixer features two unique structures (doubly interdigitated gate gratings and a vertical cavity) for higher radiation efficiencies. Its total field emission properties are the result of a combination of plasmon excitation dynamics and electromagnetic...

We performed numerical analyses on structure sensitive field emission properties of our proposing plasmon resonant photomixer (PRX) in the terahertz range. The photomixer incorporates doubly interdigitated grating strips for gate electrodes and a vertical resonator structure for realizing highly efficient terahertz emission even at room temperature. We investigated the dependence of total field...

We report on a study of terahertz (THz) generation using implanted InGaAs photomixers and multi-wavelength quantum dot lasers. We carry out InGaAs materials growth, optical characterization, device design and fabrication, and photomixing experiments. This approach is capable of generating a comb of electromagnetic radiation from microwave to terahertz. For shortening photomixer carrier lifetime...