Time domain simulation of THz photoconductive antennas

Perez, Enrique Moreno; Pantoja, Mario F.; Garcia, S.G.; Bretones, A. Rubio; Martin, R. Gomez

doi:10.1109/eucap.2012.6206351

Cited by 3 publications

(5 citation statements)

References 11 publications

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“…The 3-D image of the electrostatic potential of Fig. 5(a) depicts the abrupt change in the inner region of the electrodes, where the source laser acts, and it has been validated using a specialized CAD for electronics [33], [29]. The high value of the subsequent electrostatic fields creates a significant drift for photogenerated carriers, thus starting the physical processes to generate THz radiation.…”

Section: Resultsmentioning

confidence: 99%

“…However, the relevance of an accurate solution of the steady state should not be neglected because the physical description of the semiconductor depends strongly on the biasing electric field [26] [28]. Thus, the initial distribution of carriers and currents as well as the nonhomogeneous carrier mobilities in the semiconductor has to be inferred from the steady-state solution, as a step prior to calculating radiation parameters of the PCA [29].…”

Section: Physical Description Of Pcas At Thz Regimementioning

confidence: 99%

“…Numerical formulation of FDTD is achieved by considering the transient current , which can be calculated by using (8), (9), and (4) to yield (25) where (26) (27) (28) Source current at th timestep can be rewritten in terms of electrostatic field and time-dependent conductivity, and , respectively, as (29) Then, transient current is introduced in discrete form of Ampere's equation 7as (30) which enables a split formulation of Ampere-Maxwell and Faraday laws, of the form ( It also bears remarking that proposed procedure is prone to instabilities in the numerical solution. To avoid this, the Courant stability condition still holds for the solution of the combined drift-diffusion and FDTD scheme, but other challenging issues appear in this case which differ from the usual electromagnetic case: on one hand, the complete system of equations is nonlinear, because of the recombination function (12) appearing in (10) and (11) and, on the other hand, terms related to distribution of carriers and act as diffusive sources of the electromagnetic field.…”

Section: Numerical Solution Of Pcas At Thz Regimementioning

confidence: 99%

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Time-Domain Numerical Modeling of THz Photoconductive Antennas

Moreno

Pantoja

Garcia

et al. 2014

IEEE Trans. THz Sci. Technol.

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This paper presents a computational procedure to simulate the time-domain behavior of photoconductive antennas made of semiconductor and metal materials. Physical modeling of semiconductor devices at terahertz regime can be achieved by applying joint electronic and electromagnetic procedures, e.g., solving a coupled system of equations inferred from Poisson's drift-diffusion and Maxwell's equations. A set of discrete equations are derived by applying a combined finite-difference methodology for the previous steady-state and the finite-difference time-domain procedure for the transient regime. The results for the radiated electric field at broadside direction show good agreement with the experimental results previously reported in the literature.

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Section: Resultsmentioning

confidence: 99%

Section: Physical Description Of Pcas At Thz Regimementioning

confidence: 99%

Section: Numerical Solution Of Pcas At Thz Regimementioning

confidence: 99%

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Time-Domain Numerical Modeling of THz Photoconductive Antennas

Moreno

Pantoja

Garcia

et al. 2014

IEEE Trans. THz Sci. Technol.

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“…A femtosecond laser pulse illuminates the receivers with an approximately cylindrical spot between the contact electrodes in the gap's center. [26] The changes in the photoconductivity and current density mainly occur in the gap. [27] A yoz cross-section SΩ of the carrier concentration at the center of the gap between the metal electrodes is created to make the simulation more accurate and overcome an overestimation of the amplitude of the terahertz electric field.…”

Section: Terahertz Detection Pca Modelsmentioning

confidence: 99%

Simulation of terahertz signal reception detection based on field enhancement

Xiong,

Liu,

Shang

et al. 2023

6th Optics Young Scientist Summit (OYSS 2023)

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Simulations of terahertz signals in the time or frequency domain focus on the photoconductive antenna (PCA). However, they lack a simpler and more accurate simulation technology for PCA, which plays a crucial role in designing and optimizing detectors. Such work is essential in terahertz imaging and time-domain spectroscopy (THz-TDS). This work simulates an incident terahertz wave by introducing a three-dimensional (3-D) finite-difference time-domain (FDTD) simulation in the form of a total field to scattering field. This wave is pretreated as a plane wave that is incident on the receiver. The equation of carrier dynamics with semiconductor charge and transport is solved by using the 3-D full-wave FDTD method. A center surface current method is used to calculate the time-varying conductivity. A sampling electric field was used to evaluate the photocurrent. They were obtained by convolving the main time-varying photoconductivity of the photoexcited carrier distribution on the cross-section in the middle of the gap of a PCA receiver. Then, we compare these simulations with previously reported data from an incident terahertz signal. In addition, we simulated the detection characteristics with other results in the literature. Our simulation tool can accurately reproduce these data sets.These simulations can be used to design and optimize the receiving performance of different PCAs structures before costly fabrication has commenced.

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“…In Figure 1, the generation process of THz radiation in the PCA can be described as follows: A femtosecond laser pulse illuminates a spot in the gap between two electrodes, 18 when the photon energy of the incident femtosecond laser pulse is higher than the band gap of the semiconductor material, electron-hole pairs will be generated inside the material. Under the action of the applied bias voltage, the photoexcited carriers will be driven along the direction of the electric field to form transient current, 19 which contributes to the radiation of THz waves in the PCA.…”

Section: Physical Model and Theoretical Formulationmentioning

confidence: 99%

Numerical simulation of terahertz radiation in photoconductive antenna

Xiong

Chen

et al. 2020

Micro & Optical Tech Letters

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The terahertz radiation in photoconductive antenna involves the multiple physical processes. It is a challenge to simulate the terahertz radiation in photoconductive antenna. A numerical simulation tool for the photoconductive antenna is very necessary to effectively design and optimize the terahertz radiation source. In this paper, by introducing the auxiliary equations describing the dynamic behaviors of carriers in the semiconductor into the Maxwell's equations, we use the three‐dimensional finite‐difference time‐domain method to solve these equations and obtain the time‐domain solutions in the nearfield of antenna. A near‐to‐far‐field transformation in the layered medium is adopted in order to obtain the wave pattern of terahertz radiation in the far field. Assisted by the developed simulation tool, the terahertz time‐domain waveforms and other terahertz radiation characteristics for the photoconductive antenna can be presented. By comparing with the experimental results reported in the references, the validity and reliability of these physical models and the developed simulation tool are demonstrated. More importantly, the results given in this paper will be of great significance to design and optimize the radiation performance of photoconductive antenna with different structures.

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Time domain simulation of THz photoconductive antennas

Cited by 3 publications

References 11 publications

Time-Domain Numerical Modeling of THz Photoconductive Antennas

Time-Domain Numerical Modeling of THz Photoconductive Antennas

Simulation of terahertz signal reception detection based on field enhancement

Numerical simulation of terahertz radiation in photoconductive antenna

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