Enhanced terahertz radiation of photoconductive antenna fabricated on GaAs-on-sapphire

Zhang, Jitao; Tuo, Mingguang; Gehl, Michael; Gibson, Ricky; Liang, Min; Xin, Hao

doi:10.1063/1.5127877

Cited by 5 publications

(2 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The antenna structures were fabricated on the GaAs-onsapphire wafer by optical lithography and lift-off techniques. 51 The metallic layer was made of 40 nm Cr/200 nm Au. A passivation layer of SiO 2 was deposited on the top of the gap region to improve the optical transmission and thermal properties of the device.…”

Section: Cancellation Effectmentioning

confidence: 99%

Contribution assessment of antenna structure and in-gap photocurrent in terahertz radiation of photoconductive antenna

Zhang

Tuo

Liang

et al. 2018

Journal of Applied Physics

Self Cite

View full text Add to dashboard Cite

Photoconductive antenna (PCA) is one of the most widely used terahertz (THz) devices nowadays. Although PCAs have been extensively studied through both theoretical analysis and device design, there still lacks a common agreement upon the mechanism of THz radiation. One of the central questions is how to distinguish and assess the contribution of the antenna structure and in-gap photocurrent to the overall radiation of a PCA. In this work, a three-dimensional full-wave model was first used to quantify the overall far-field radiation of PCAs. The commercial solver (i.e., HFSS) and the Hertzian dipole approximation method were then applied to quantify the far-field radiation solely from the antenna structure and in-gap photocurrent, respectively. The contribution of the antenna structure and in-gap photocurrent can therefore be distinguished by comparing the simulation results among the three methods. The results suggest that, although the THz radiation originates from laser-excited photocurrent within the gap, the overall THz radiation of a PCA is predominated by the antenna structure. As a validation, the cancellation effect was predicated by numerical simulation of coplanar stripline PCA and confirmed with experiment using butterfly shaped stripline PCA. The presented work uncovers the details of the underlying radiation mechanism of the PCA. This could inspire PCA design that aims for engineering the radiation properties of a PCA for specific applications.

show abstract

Section: Cancellation Effectmentioning

confidence: 99%

Contribution assessment of antenna structure and in-gap photocurrent in terahertz radiation of photoconductive antenna

Zhang

Tuo

Liang

et al. 2018

Journal of Applied Physics

Self Cite

View full text Add to dashboard Cite

show abstract

“…The first is an optical method in which the laser beam (frequencies in the THz range (10 15 Hz), mainly pulsed, with low power) is converted to the THz range [3]. Nonlinear crystals [4], photoconductive antennas [5] and free electron lasers (FEL-Free Electron Laser) [6] are used to achieve the THz range. The second method is the so-called electronic method, where microwaves (frequencies in the GHz range, mainly continuous waves and higher powers) are converted up to the THz range [2].…”

Section: Introductionmentioning

confidence: 99%

Position Sensing with a Compact 0.1 THz Amplitude Modulated Source

2022

View full text Add to dashboard Cite

Position determination is an important manufacturing process in many modern industries. The objective of this paper is to present an affordable measurement system that can replace optical position measurement with a laser beam in an opaque environment that prevents the laser beam from penetrating through the fog of gases or other materials that are opaque to optical light. THz waves are a good example of replacing a laser beam, as shown in this article. It is known that THz rays can penetrate fabrics, wood, Styrofoam, etc. The triangulation method using an amplitude modulated THz source proved to be a cost-effective solution for position determination in opaque environments.

show abstract

How to maximize the bandwidth without increasing the noise in op-amp-based transimpedance amplifiers using positive feedback

Yang

Cui

et al. 2022

Review of Scientific Instruments

View full text Add to dashboard Cite

The bandwidth of very high gain (≥100 MV/A) transimpedance amplifiers is restricted to below 100 kHz, unless measures are employed to mitigate the effect of circuit parasitic capacitances. Current approaches involve significantly increased circuit complexity and component count. They may suffer unwanted noise pickup or destructive capacitive coupling to ground, the latter restricting the available bandwidth. We demonstrate that combining a positive feedback circuit with a low-pass filter network extends the bandwidth of a transimpedance amplifier out to the limit of gain peaking (>1 MHz) without increasing the noise signal. The circuit uses a single inverting amplifier and very large feedback-resistance to provide a canceling parasitic-capacitance positive feedback signal. This can negate both the negative feedback-resistor parasitic-capacitance and the input/output pin parasitic-capacitance of the transimpedance amplifier. The circuit solves the problem of destructive distributed-capacitive coupling to ground along the feedback resistor.

show abstract

Enhanced terahertz radiation of photoconductive antenna fabricated on GaAs-on-sapphire

Cited by 5 publications

References 22 publications

Contribution assessment of antenna structure and in-gap photocurrent in terahertz radiation of photoconductive antenna

Contribution assessment of antenna structure and in-gap photocurrent in terahertz radiation of photoconductive antenna

Position Sensing with a Compact 0.1 THz Amplitude Modulated Source

How to maximize the bandwidth without increasing the noise in op-amp-based transimpedance amplifiers using positive feedback

Contact Info

Product

Resources

About