Metal-Grating-Coupled Terahertz Quantum-Well Photodetectors

Zhang, R; Guo, Xuguang; Song, Chunying; Buchanan, M.; Wasilewski, Z. R.; Cao, Juncheng; Liu, H C

doi:10.1109/led.2011.2112632

Cited by 34 publications

(12 citation statements)

References 10 publications

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“…To date, THz QWIPs have mainly been embedded in large (compared with the wavelength) photonic structures such as mesas (normally substrate-coupled through a polished facet) [13,15] or metal diffraction gratings [20]. More recently, arrays of diffraction-limited (λ/2) patch antennas [21] and planar meta-material surfaces [22] have been used to couple radiation into THz quantum well detectors.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast terahertz detectors based on three-dimensional meta-atoms

Paulillo¹,

Pirotta²,

Nong³

et al. 2017

Optica

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Terahertz (THz) and sub-THz frequency emitter and detector technologies are receiving increasing attention, underpinned by emerging applications in ultra-fast THz physics, frequency-combs technology and pulsed laser development in this relatively unexplored region of the electromagnetic spectrum. In particular, semiconductor-based ultrafast THz receivers are required for compact, ultrafast spectroscopy and communication systems, and to date, quantum well infrared photodetectors (QWIPs) have proved to be an excellent technology to address this given their intrinsic ps-range response However, with research focused on diffraction-limited QWIP structures (lambda/2), RC constants cannot be reduced indefinitely, and detection speeds are bound to eventually meet un upper limit. The key to an ultra-fast response with no intrinsic upper limit even at tens of GHz is an aggressive reduction in device size, below the diffraction limit. Here we demonstrate sub-wavelength (lambda/10) THz QWIP detectors based on a 3D split-ring geometry, yielding ultra-fast operation at a wavelength of around 100 {\mu}m. Each sensing meta-atom pixel features a suspended loop antenna that feeds THz radiation in the ~20 m3 active volume. Arrays of detectors as well as single-pixel detectors have been implemented with this new architecture, with the latter exhibiting ultra-low dark currents below the nA level. This extremely small resonator architecture leads to measured optical response speeds - on arrays of 300 devices - of up to ~3 GHz and an expected device operation of up to tens of GHz, based on the measured S-parameters on single devices and arrays

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Section: Introductionmentioning

confidence: 99%

Ultrafast terahertz detectors based on three-dimensional meta-atoms

Paulillo¹,

Pirotta²,

Nong³

et al. 2017

Optica

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show abstract

“…Such limitation leads to a low signal coupling efficiency. Therefore, many coupling structures have been applied to improve the signal coupling efficiency of THz detector, for example, the extended hemispherical lens 8 , diffractive lens 9 , F-P air cavity 10 – 12 and metal grating coupler 13 , 14 , etc. However, the sizes of the extended hemispherical lens and the diffractive lens are much larger than that of the detector.…”

Section: Introductionmentioning

confidence: 99%

Reflective grating-coupled structure improves the detection efficiency of THz array detectors

Xiao

Kang

et al. 2018

Sci Rep

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A reflective grating-coupled structure on the silicon substrate was designed to improve the detection efficiency of terahertz detectors for the frequency ranging from 0.26 THz to 0.36 THz. By using finite difference time domain (FDTD) solutions, the simulation and optimized design of the grating-coupled structure were carried out. The results showed that the signal was effectively reflected and diffracted by the reflective grating-coupled structure which significantly enhanced the electric field in the place of the detector. The maximum electric field can be increased by 2.8 times than that of the Fabry-Perot resonator. To verify the design results, the reflective grating-coupled structure was applied in the preparation of the Nb5N6 array detector chip and compared with the Nb5N6 array detector chip with the F-P resonator. The results showed that the maximum voltage responsivity of the Nb5N6 detector with the reflective grating-coupled structure was 2 times larger than the Nb5N6 detector with the F-P resonator. It indicates that the reflective grating-coupled structure can efficiently improve the detection efficiency of THz detectors.

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“…4 During the past decade, many theoretical and experimental works about terahertz QWPs and terahertz quantum-dot detectors are carried out. [5][6][7][8][9][10][11][12][13] Due to the threedimensional confinement effects, the terahertz quantum-dot detectors can work in temperatures of more than 100 K. 11,12 The results show that such detectors become more and more promising for their potential applications in fast, integrated, and compact terahertz systems. 2 As is well known, metal grating and other periodic metal structures are widely adopted to enhance optical absorption in many detectors.…”

mentioning

confidence: 99%

“…2 As is well known, metal grating and other periodic metal structures are widely adopted to enhance optical absorption in many detectors. [13][14][15] Especially for QWPs working in infrared and terahertz spectral regions, due to the polarization selection rule for intersubband transition, diffraction grating couplers must be used to diffract the normal incident light and achieve the electrical field component perpendicular to the quantum-well plane that can be absorbed by intersubband transition. In our previous work, 16 except for a photoresponse peak at 5.7 THz corresponding to bound-to-bound intersubband transition, there is an extra strong and sharp photocurrent peak at longitudinal optical (LO) phonon frequency (8.87 THz) in a one-dimensional (1D) metal-grating-coupled terahertz QWP.…”

mentioning

confidence: 99%