Optical absorption enhancement in LTG-GaAs for efficiency improvement of THz photoconductive antennas

Bashirpour, Mohammad; Ghorbani, S.; Forouzmehr, Matin; Neshat, Mohammad

doi:10.1109/mmwatt.2016.7869865

Cited by 8 publications

(4 citation statements)

References 8 publications

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“…πqμ 2 e ΔtAn t ðÞ V 2 c t ðÞ 4S g (10) where, Δt is the time step. The total current flowing through the circuit is calculated using the Eq.…”

Section: Theoretical Modeling Of Ipcamentioning

confidence: 99%

“…However, there is the issue of low optical-to-THz conversion efficiency [3,4]. Efforts have been made to enhance the efficiency by improving the laser pulse coupling, including the use of anti-reflection coating on Low-Temperature-grown Gallium Arsenide (LT-GaAs) [5], AlAs-AlGaAs based Bragg reflector under the LT-GaAs layer [6], nanoplasmonic structures [7], nanoplasmonic double layer structure [8,9], recessed electrode and recessed nanoplasmonic array, nano-spaced electrodes [10], optical plasmonic nano-antenna [11], plasmonic nanostructure [12], graphene [13].…”

Section: Introductionmentioning

confidence: 99%

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Interdigitated Photoconductive Antenna for Efficient Terahertz Generation and Detection

Mondal¹,

Edwin²,

Rathinasamy³

2022

Terahertz Technology

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THz signals can be generated commonly from Photoconductive Antenna (PCA) but the efficiency is low for the conventional PCA. This work improves the optical to terahertz conversion efficiency of the terahertz radiation by changing the conventional PCA structure to Interdigitated PCA (IPCA). The efficiency of PCA is dependent on the current pulse generated in the antenna structure when the laser pulse is incident on it. This paper targets to achieve high photo-current, as well as THz electric field from the IPCAs which are simulated using FEM and FDTD techniques. Also, the effect of various parameters such as current, gain, frequency bandwidth, optical to terahertz conversion efficiency, etc. are studied to study the importance of IPCAs.

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“…πqμ 2 e ΔtAn t ðÞ V 2 c t ðÞ 4S g (10) where, Δt is the time step. The total current flowing through the circuit is calculated using the Eq.…”

Section: Theoretical Modeling Of Ipcamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Interdigitated Photoconductive Antenna for Efficient Terahertz Generation and Detection

Mondal¹,

Edwin²,

Rathinasamy³

2022

Terahertz Technology

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show abstract

“…However, the low optical-to-THz conversion efficiency is an important problem [7]. Studies in order to enhance the efficiency such as the use of antireflection coating on low-temperature-grown gallium arsenide (LT-GaAs) [8], AlAs-AlGaAs based Bragg reflector under the LT-GaAs layer [9], nano-plasmonic structures [10], nanoplasmonic double layer structure [11], recessed electrode and recessed nano-plasmonic array, nano-spaced electrodes [12], graphene [13], plasmonic nanostructure [14], and optical plasmonic nano-antenna [15]. The coherent THz synchrotron radiation is also an important challenge for scientists and various studies tried to obtain the coherent THz.…”

Section: Introductionmentioning

confidence: 99%

Generating High Efficiency Terahertz Radiation From Relativistic Nano-Bunches in the Interaction of Ultrarelativistic Lasers With Thin Solid Targets

Moshkelgosha

Tavakoli

2022

IEEE Trans. Plasma Sci.

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The interaction of femtosecond laser pulses with thin solid targets is one of the most efficient methods to obtain terahertz (THz) radiation. In the specific conditions, the electron of plasma surface distribution became so localized and nanobunches are formed which causes coherent synchrotron emission (CSE). In this mechanism which occurs when the relativistic laser is obliquely incident on plasma, the plasma electrons gather in a very dense and thin layer of nanometer width. The electrons of nano-bunch can emit intense coherent emissions in different ranges of electromagnetic radiation. In this study, producing high-efficiency THz radiating from relativistic nano-bunches is discussed. The effect of plasma and nano-bunch parameters, the mobility of ions, the initial thermal velocity of electrons, and the speed of electrons are investigated. According to the results, the direct relation between the width of the nano-bunch and the efficiency is seen. The nonlinear relation between the initial thermal velocity of electrons and the THz yield is seen. In the desirable conditions, a high THz yield of up to 37% is obtained from nano-bunches with the initial thermal velocities as 0.3 of light speed.

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“…For the purpose enhance the radiation efficiencies of PCAs and enhance the effects of terahertz radiation, many preparation attempts have been made like changing the electrode shape [1,[7][8][9][10][11][12][13][14][15][16][17], incorporating plasmonic structures [18][19][20][21][22][23][24][25] or mixed structure [26][27][28], and surface treatment [29,30].…”

Section: Introductionmentioning

confidence: 99%

Terahertz radiation enhancement based on LT-GaAs by optimized plasmonic nanostructure

Jiang¹,

Cheng²,

Li³

et al. 2021

Laser Phys.

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Terahertz waves have unique penetrability, safety, spectral resolution, and many other useful properties. Therefore, terahertz waves are widely employed in medical treatment, detection, imaging, security, and spectroscopy. They also possess great development prospects in photoconductive antennas (PCAs) for telecommunication and other devices. However, terahertz PCAs are still limited by the weak photocurrents and small light absorption rates, making the development of PCAs with improved conversion efficiencies highly desirable. In this study, a new type of plasmonic PCAs with high photoelectric conversion efficiency was proposed. The interaction between the 800 nm fs laser and staggered nanorods was studied by the finite difference time domain (FDTD) method. The geometric parameters of the nanorods arrays were optimized. Compared to conventional photoconductive antennas without nanostructures, the PCAs with optimized nano-plasmonic structure I showed threefold higher electric field radiations under 800 nm fs laser irradiation. Optimized plasmonic nanostructure II increases photocurrent up to 335.553 nA that indicates 10 times enhancement in comparison with conventional structure. Hence, the developed structures greatly enhanced the light absorption of the photosensitive layer based on low-temperature-grown gallium arsenide. In sum, the proposed staggered hexagonal plasmonic structures (structure II) could effectively improve the light-terahertz conversion efficiencies of PCAs.

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Optical absorption enhancement in LTG-GaAs for efficiency improvement of THz photoconductive antennas

Cited by 8 publications

References 8 publications

Interdigitated Photoconductive Antenna for Efficient Terahertz Generation and Detection

Interdigitated Photoconductive Antenna for Efficient Terahertz Generation and Detection

Generating High Efficiency Terahertz Radiation From Relativistic Nano-Bunches in the Interaction of Ultrarelativistic Lasers With Thin Solid Targets

Terahertz radiation enhancement based on LT-GaAs by optimized plasmonic nanostructure

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