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The origin of distorted intensity pattern sensed by a lens and antenna coupled AlGaN/GaN-HEMT terahertz detectors
摘要： Here, we report artefacts in the intensity pattern of a focused terahertz beam around 1 THz by scanning photocurrents as a function of the beam location and the frequency. Although the exact distortion is found with our specific antenna design, we believe similar artefacts could be commonplace in antenna-coupled FET terahertz detectors when the beam spot becomes comparable with the antenna size. To eliminate such artefact, new antenna designs are welcomed to achieve strong asymmetry in the terahertz field distribution under the gate while maintaining a more symmetric radiation pattern for the whole antenna.
关键词： high electron mobility transistor,terahertz detector,self-mixing,local electrical field
更新于2025-09-23 15:19:57
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[IEEE ESSCIRC 2019 - IEEE 45th European Solid State Circuits Conference (ESSCIRC) - Cracow, Poland (2019.9.23-2019.9.26)] ESSCIRC 2019 - IEEE 45th European Solid State Circuits Conference (ESSCIRC) - A Hybrid THz Imaging System With a 100-Pixel CMOS Imager and a 3.25a??3.50 THz Quantum Cascade Laser Frequency Comb
摘要： The terahertz frequency range beyond 3 THz has exciting potential to have a transformative impact in a wide range of applications, including chemical and biomedical sensing, spectroscopy, imaging, and short-distance wireless communication. While there have been significant advancements in silicon-based THz imagers in the frequency ranges below 1 THz, technological development beyond 3 THz has been impeded by the lack of solid-state sources in this frequency range. In addition, the design space beyond 3 THz opens up fundamentally new challenges across electronics and the electromagnetic interface. In this spectral range, the wavelength is small enough (λox ≈ 50 μm at 3 THz) that a vertical via from the top antenna layer to the detector is a distributed element (transmission line or radiator). In this letter, we follow a careful circuits-electromagnetics co-design approach toward a hybrid imaging system with a 100-pixel CMOS imager that interfaces with a THz quantum cascade laser frequency comb that spans 3.25–3.5 THz with mode spacing of 17 GHz. The array chip, while designed for an optimal operation across 2.7–2.9 THz, demonstrates an average noise equivalent power (NEP) (across pixels) of 1260 pW/√Hz between 3.25–3.5 THz and a projected NEP of 284 pW/√Hz across the design range of 2.7–2.9 THz. To the best of our knowledge, we demonstrate for the first time full THz imaging in a hybrid quantum cascade laser (QCL)–CMOS fashion. This approach allows future works to leverage both QCL and CMOS technologies to demonstrate new technological advances for systems in the 1–10 THz range.
关键词： quantum cascade laser,THz imaging,terahertz,detector,imaging,CMOS,silicon,hybrid imaging
更新于2025-09-23 15:19:57
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[IEEE 2019 14th European Microwave Integrated Circuits Conference (EuMIC) - Paris, France (2019.9.30-2019.10.1)] 2019 14th European Microwave Integrated Circuits Conference (EuMIC) - A Broadband Antenna-Coupled Terahertz Direct Detector in a 0.13-μm SiGe HBT Technology
摘要： This paper presents an integrated silicon-lens coupled THz direct detector. It comprises a pair of differentially driven antenna-coupled HBT transistors in common-base configuration implemented in an advanced 0.13-μm SiGe HBT technology with fT/fmax of 350/550 GHz. Based on the antenna detector co-design approach, a broadband operation with an optical noise equivalent power (NEP) lower than 40 pW/√Hz in the measured 220 GHz to 1 THz band is achieved. The detector operates in a voltage mode readout with an external resistance of 1.83 k?. Two device regions have been investigated. In the forward-active mode the detector achieves its minimum NEP of 1.9 pW/√Hz from 275 to 525 GHz at 100 kHz chopping frequency. The maximum voltage responsivities (Rv) are 9 kV/W and around 7.5 kV/W respectively. In the saturation region the minimum measured NEP from 220 GHz to 1 THz is 5.1 pW/√Hz at 292 GHz and values less than 4.3 pW/√Hz.
关键词： HBT,NEP,SiGe,on-chip antenna,Terahertz detector
更新于2025-09-12 10:27:22
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Compact and ultra-efficient broadband plasmonic terahertz field detector
摘要： Terahertz sources and detectors have enabled numerous new applications from medical to communications. Yet, most efficient terahertz detection schemes rely on complex free-space optics and typically require high-power lasers as local oscillators. Here, we demonstrate a fiber-coupled, monolithic plasmonic terahertz field detector on a silicon-photonics platform featuring a detection bandwidth of 2.5 THz with a 65 dB dynamical range. The terahertz wave is measured through its nonlinear mixing with an optical probe pulse with an average power of only 63 nW. The high efficiency of the scheme relies on the extreme confinement of the terahertz field to a small volume of 10?8(λTHz/2)3. Additionally, on-chip guided plasmonic probe beams sample the terahertz signal efficiently in this volume. The approach results in an extremely short interaction length of only 5 μm, which eliminates the need for phase matching and shows the highest conversion efficiency per unit length up to date.
关键词： plasmonic,nonlinear mixing,silicon-photonics,terahertz,detector
更新于2025-09-12 10:27:22