Terahertz Generation Using Implanted InGaAs Photomixers and Multi-wavelength Quantum Dot Lasers

Abstract

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, we employ proton implantation into an epitaxial layer of lattice matched InGaAs grown on InP. Under a 1.55 μm multi-mode InGaAs/InGaAsP quantum dot laser excitation, a frequency comb with a constant frequency spacing of 50 GHz generated on the photomixer is measured, which corresponds to the beats of the laser longitudinal modes. The measurement is performed with a Fourier transform infrared spectrometer. This approach affords a convenient method to achieve a broadband multi-peak coherent THz source.

Enhancement of terahertz photoconductive antenna operation by optical nanoantennas

“…The metal dipole NAs are used in THz photoconductive antennas and photomixers, enhancing an optical field of pump laser and redistributing it into the surface layer of the semiconductor substrate near the electrodes. The first implementation of dipole NAs embedded inside the gap of THz antenna are interdigitated nanostructured electrodes, or as they often called, “nano‐fingers” . Fig.…”

“…The first implementation of dipole nanoantennas embedded inside the gap of THz antenna are interdigitated nanostructured electrodes, or as they often called, "nanofingers" [86,110,120,[138][139][140]. Figure 11(a) presents a interdigitated nanostructures embedded in the gap between the electrodes of the logarithmic photomixer.…”

Single-Crystalline InGaAs Nanowires for Room-Temperature High-Performance Near-Infrared Photodetectors

“…As an important III–V ternary semiconductor, InGaAs are expected to have potential bandgap tunability from the near-infrared (NIR) to mid-infrared (MIR) region (0.35 ≤ E g ≤ 1.42 eV). Due to its tunable bandgap, as well as high electron mobility and small leakage current, In x Ga 1−x As nanowires have been widely used in optoelectronic devices, such as NIR emission lasers, photovoltaics, and field-effect transistors [ 18 – 20 ]. Till now photodetectors based on InGaAs quantm dots and films have been fabricated.…”

Metallic and dielectric metasurfaces in photoconductive terahertz devices: a review

“…In general, THz photomixers commonly utilize interdigitated electrodes, which allows for effectively increasing both the length of the metalsemiconductor interface and the active area for the THz generation. [73][74][75][76][77] Recently, using the modified photomixer electrodes featuring a tip-to-tip topology that provides strong THz field enhancement with good impedance matching to antenna and exhibits a lower RC time constant allowing the enhancement of the THz intensity in the high-frequency region of the THz spectrum was proposed. 78,79 Meanwhile, the tip-to-tip topology implies that the subwavelength electrode gaps to employ plasmonic effects to increase the electric field in close proximity to the electrodes.…”