Abstract-The Route to Nanoscale Terahertz Technology: Nanowire-based Terahertz Detectors and Terahertz Modulators

Jessica L Boland, Kun Peng, Sarwat Baig, Diamshid Damry, Patrick Parkinson, Lan Fu, Hark Hoe Tan,  

https://ieeexplore.ieee.org/document/8510319

In this work, we demonstrate novel THz detectors and modulators based on semiconductor nanowires. We show that single nanowire PC THz receivers exhibit excellent sensitivity, high SNR of 40, and a broad detection bandwidth up to 2 THz, comparable to the bulk InP PC receivers. We also demonstrate ultrafast THz modulation by GaAs nanowire polarisers with a less than 5ps switching time and a modulation depth of -8dB, We show an extinction of over 13% and dynamic range of -9dB, comparable to microsecond-switchable graphene- and metamaterial-based THz modulators.

Abstract-A Terahertz Controlled-NOT Gate Based on Asymmetric Rotation of Polarization in Chiral Metamaterials

Wei-Zong Xu, Ya-Ting Shi, Jiandong Ye, Fang-Fang Ren, Ilya V. Shadrivov, Hai Lu, Lanju Liang, Xiaopeng Hu, Biaobing Jin, Rong Zhang, Youdou Zheng, Hark Hoe Tan, Chennupati Jagadish

http://onlinelibrary.wiley.com/doi/10.1002/adom.201700108/abstract

Logical operation based on polarization encoding of light is important for future data transmission and information processing. However, in the terahertz (THz) region, chiral materials with large optical activity are not available in nature, and the effective manipulation of polarization states remains challenging. Here, the authors demonstrate a double-layer bi-anisotropic metamaterial that consists of planar spiral and cut-wire layers separated by a polyimide film. Strong asymmetric polarization rotation of two orthogonal linear polarizations can be observed around 0.53 THz. By investigating the correlation between two linear polarization states before and after the spiral-wire metamaterial at this frequency, a controlled-NOT (CNOT) gate operating on two linear-polarization-based qubits is further exploited. The processing mechanism of the asymmetric rotation and CNOT gate is attributed to the scattering of dipole momentum based on classical multipole theory. This polarization processor's architecture is promising for robust and energy-efficient THz polarization control, and also provides an effective path for the development of future optical supercomputing technology.

Abstract-Single n+-i-n+ InP nanowires for highly sensitive terahertz detection

Kun Peng1, Patrick Parkinson2, Qian Gao1, Jessica L Boland3, Ziyuan Li1, Fan Wang4, 
Sudha Mokkapati5, Lan Fu1,6, Michael B Johnston3,6, Hark Hoe Tan1 and Chennupati Jagadish

http://iopscience.iop.org/article/10.1088/1361-6528/aa5d80

Developing single-nanowire terahertz (THz) electronics and employing them as sub-wavelength components for highly-integrated THz time-domain spectroscopy (THz-TDS) applications is a promising approach to achieve future low-cost, highly integrable and high-resolution THz tools, which are desirable in many areas spanning from security, industry, environmental monitoring and medical diagnostics to fundamental science. In this work, we present the design and growth of n+-i-n+ InP nanowires. The axial doping profile of the n+-i-n+ InP nanowires has been calibrated and characterized using combined optical and electrical approaches to achieve nanowire devices with low contact resistances, on which the highly-sensitive InP single-nanowire photoconductive THz detectors have been demonstrated. While the n+-i-n+ InP nanowire detector has a only pA-level response current, it has a 2.5 times improved signal-to-noise ratio compared with the undoped InP nanowire detector and is comparable to traditional bulk THz detectors. This performance indicates a promising path to nanowire-based THz electronics for future commercial applications.

Abstract-Broad Band Phase Sensitive Single InP Nanowire Photoconductive Terahertz Detectors

Kun Peng, Patrick Parkinson, Jessica L. Boland, Qian Gao, Yesaya C. Wenas, Christopher Davies, Ziyuan Li, Lan Fu, Michael B Johnston, Hark Hoe Tan, and Chennupati Jagadish

Nano Lett., Just Accepted Manuscript

DOI: 10.1021/acs.nanolett.6b01528

Publication Date (Web): July 14, 2016

Copyright © 2016 American Chemical Society

http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.6b01528
Terahertz time-domain spectroscopy (THz-TDS) has emerged as a powerful tool for materials characterization and imaging. A trend towards size reduction, higher component integration and performance improvement for advanced THz-TDS systems is of increasing interest. The use of single semiconducting nanowires for terahertz (THz) detection is a nascent field that has great potential to realize future highly-integrated THz systems. In order to develop such components, optimized material optoelectronic properties and careful device design are necessary. Here, we present antenna-optimized photoconductive detectors based on single InP nanowires with superior properties of high carrier mobility (∽1260 cm2V-1s-1) and low dark current (∼10 pA), which exhibit excellent sensitivity and broadband performance. We demonstrate that these nanowire THz detectors can provide high quality time-domain spectra for materials characterization in a THz-TDS system, a critical step towards future application in advanced THz-TDS system with high spectral and spatial resolution.

Abstract-Single Nanowire Photoconductive Terahertz Detectors

Kun Peng , Patrick Parkinson , Lan Fu , Qiang Gao , Nian Jiang , Yanan Guo , Fan Wang , Hannah J Joyce , Jessica L Boland , Hark Hoe Tan , Chennupati Jagadish , and Michael B Johnston

Nano Lett., Just Accepted Manuscript

DOI: 10.1021/nl5033843

Publication Date (Web): December 9, 2014

Copyright © 2014 American Chemical Society

http://pubs.acs.org/doi/abs/10.1021/nl5033843

Spectroscopy and imaging in the terahertz (THz) region of the electromagnetic spectrum has proven to provide important insights in fields as diverse as chemical analysis, materials characterization, security screening and non-destructive testing. However, compact optoelectronics suited to the most powerful terahertz technique – time-domain spectroscopy – are lacking. Here, we implement single GaAs nanowires as microscopic coherent THz sensors and for the first time incorporated them into the pulsed time-domain technique. We also demonstrate the functionality of the single nanowire THz detector as a spectrometer by using it to measure the transmission spectrum of a 290 GHz low pass filter. Thus nanowires are shown to be well suited for THz device applications, and hold particular promise as near-field terahertz sensors.