Photoconductive Semiconductor-Based Optoelectronic Devices for Generation of Terahertz Radiation

2021 ◽  
Vol 23 (2) ◽  
pp. 82-87
Author(s):  
Ponomarev D.S. ◽  
Keyword(s):  
Pump Power ◽  
Bias Voltage ◽  
Terahertz Radiation ◽  
Dynamic Range ◽  
Optoelectronic Devices ◽  
Imaging Systems ◽  
Material Base ◽  
Photoconductive Antenna ◽  
Frequency Bandwidth ◽  
Thz Power

We report on the development and fabrication of a superlattice-based InAlAs/InGaAs heterostructure featuring an ultrashort photocarrier lifetime which has been used as a material base for a photoconductive antenna (PCA)-emitter with a frequency bandwidth of 10 GHz — 3.0 THz and dynamic range above 60 dB. We show an efficiency of plasmonic electrodes embedded into the 10 μm PCA’s gap demonstrating the enhancement of the emitted THz power up to 10 μW (at bias voltage 20—30 V and average pump power 10 mW). The results could open a pathway towards the development of the Russian THz spectroscopic and imaging systems.

scholarly journals A modulation-doped heterostructure-based terahertz photoconductive antenna emitter with recessed metal contacts

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jessica Afalla ◽  
Alexander De Los Reyes ◽  
Neil Irvin Cabello ◽  
Victor DC Andres Vistro ◽  
Maria Angela Faustino ◽  
...  
Keyword(s):  
Dynamic Range ◽  
High Mobility ◽  
Optical Power ◽  
Photoconductive Antenna ◽  
Metal Contacts ◽  
Metal Electrodes ◽  
Order Of Magnitude ◽  
Dimensional Electron Gas ◽  
Reference Samples ◽  
Thz Power

AbstractWe present the implementation of an efficient terahertz (THz) photoconductive antenna (PCA) emitter design that utilizes high mobility carriers in the two-dimensional electron gas (2DEG) of a modulation-doped heterostructure (MDH). The PCA design is fabricated with recessed metal electrodes in direct contact with the 2DEG region of the MDH. We compare the performance of the MDH PCA having recessed contacts with a PCA fabricated on bulk semi-insulating GaAs, on low temperature-grown GaAs, and a MDH PCA with the contacts fabricated on the surface. By recessing the contacts, the applied bias can effectively accelerate the high-mobility carriers within the 2DEG, which increases the THz power emission by at least an order of magnitude compared to those with conventional structures. The dynamic range (62 dB) and bandwidth characteristics (3.2 THz) in the power spectrum are shown to be comparable with the reference samples. Drude-Lorentz simulations corroborate the results that the higher-mobility carriers in the MDH, increase the THz emission. The saturation characteristics were also measured via optical fluence dependence, revealing a lower saturation value compared to the reference samples. The high THz conversion efficiency of the MDH-PCA with recessed contacts at low optical power makes it an attractive candidate for THz-time domain spectroscopy systems powered by low power fiber lasers.

scholarly journals A Novel MEMS Capacitive Microphone with Semiconstrained Diaphragm Supported with Center and Peripheral Backplate Protrusions

Micromachines ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 22
Author(s):  
Shubham Shubham ◽  
Yoonho Seo ◽  
Vahid Naderyan ◽  
Xin Song ◽  
Anthony J. Frank Frank ◽  
...  
Keyword(s):  
Bias Voltage ◽  
Hearing Aids ◽  
High Performance ◽  
Dynamic Range ◽  
Effective Area ◽  
Film Stress ◽  
Stress Effect ◽  
Applied Bias ◽  
Simply Supported ◽  
Lumped Element Model

Audio applications such as mobile phones, hearing aids, true wireless stereo earphones, and Internet of Things devices demand small size, high performance, and reduced cost. Microelectromechanical system (MEMS) capacitive microphones fulfill these requirements with improved reliability and specifications related to sensitivity, signal-to-noise ratio (SNR), distortion, and dynamic range when compared to their electret condenser microphone counterparts. We present the design and modeling of a semiconstrained polysilicon diaphragm with flexible springs that are simply supported under bias voltage with a center and eight peripheral protrusions extending from the backplate. The flexible springs attached to the diaphragm reduce the residual film stress effect more effectively compared to constrained diaphragms. The center and peripheral protrusions from the backplate further increase the effective area, linearity, and sensitivity of the diaphragm when the diaphragm engages with these protrusions under an applied bias voltage. Finite element modeling approaches have been implemented to estimate deflection, compliance, and resonance. We report an 85% increase in the effective area of the diaphragm in this configuration with respect to a constrained diaphragm and a 48% increase with respect to a simply supported diaphragm without the center protrusion. Under the applied bias, the effective area further increases by an additional 15% as compared to the unbiased diaphragm effective area. A lumped element model has been also developed to predict the mechanical and electrical behavior of the microphone. With an applied bias, the microphone has a sensitivity of −38 dB (ref. 1 V/Pa at 1 kHz) and an SNR of 67 dBA measured in a 3.25 mm ´ 1.9 mm ´ 0.9 mm package including an analog ASIC.

scholarly journals Terahertz Field Confinement in Nonlinear Metamaterials and Near-Field Imaging

Photonics ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 22 ◽  
Author(s):  
George Keiser ◽  
Pernille Klarskov
Keyword(s):  
Terahertz Radiation ◽  
Terahertz Spectroscopy ◽  
Near Field ◽  
Terahertz Imaging ◽  
Imaging Systems ◽  
Near Field Imaging ◽  
Nonlinear Metamaterials ◽  
Terahertz Devices ◽  
Field Imaging ◽  
Sub Wavelength

This article reviews recent advances in terahertz science and technology that rely on confining the energy of incident terahertz radiation to small, very sub-wavelength sized regions. We focus on two broad areas of application for such field confinement: metamaterial-based nonlinear terahertz devices and terahertz near-field microscopy and spectroscopy techniques. In particular, we focus on field confinement in: terahertz nonlinear absorbers, metamaterial enhanced nonlinear terahertz spectroscopy, and in sub-wavelength terahertz imaging systems.

Numerical simulation of terahertz radiation in photoconductive antenna

2020 ◽  
Vol 62 (8) ◽  
pp. 2708-2714
Author(s):  
Zhong‐gang Xiong ◽  
Hu Deng ◽  
Jun‐xue Chen ◽  
Lin‐yu Chen ◽  
Quan‐chen Liu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Terahertz Radiation ◽  
Photoconductive Antenna
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