Terahertz Electro-Optic Sampling in Thick ZnTe Crystals Below the Reststrahlen Band With a Broadband Femtosecond Laser

Wu, Bihu; Cao, Lei; Zhang, Zhe; Fu, Qiang; Xiong, Yongqian

doi:10.1109/tthz.2018.2810018

Cited by 17 publications

(6 citation statements)

References 40 publications

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“…In the TDS measurement system (Advantest TAS7500TS), two optical fiber lasers (pulse duration 50 fs, center wavelength 1.55 μm, repetition frequency 50 MHz, average power 20 mW) were used in both THz generation and detection by photoconductive antenna [ 39 ]. The measurement is carried out in the dry air environment and the speed without mechanical delay line is fast (8 ms per scan), with an average time of 10 s for each sample.…”

Section: Application Examplesmentioning

confidence: 99%

A General Neural Network Model for Complex Refractive Index Extraction of Low-Loss Materials in the Transmission-Mode THz-TDS

Zhou

Jia

Cao

2022

Sensors

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The complex refractive index for low-loss materials is conventionally extracted by either approximate analytical formula or numerical iterative algorithm (such as Nelder-Mead and Newton-Raphson) based on the transmission-mode terahertz time domain spectroscopy (THz-TDS). A novel 4-layer neural network model is proposed to obtain optical parameters of low-loss materials with high accuracy in a wide range of parameters (frequency and thickness). Three materials (TPX, z-cut crystal quartz and 6H SiC) with different dispersions and thicknesses are used to validate the robustness of the general model. Without problems of proper initial values and non-convergence, the neural network method shows even smaller errors than the iterative algorithm. Once trained and tested, the proposed method owns both high accuracy and wide generality, which will find application in the multi-class object detection and high-precision characterization of THz materials.

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Section: Application Examplesmentioning

confidence: 99%

A General Neural Network Model for Complex Refractive Index Extraction of Low-Loss Materials in the Transmission-Mode THz-TDS

Zhou

Jia

Cao

2022

Sensors

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“…Usually, thin layers are needed for broadband detection. However, thick crystals may also be employed if coupled with a broadband laser [133].…”

Section: Mixing With Other Radiation; Heterodyne Detection; Downconve...mentioning

confidence: 99%

A review of terahertz detectors

Lewis

2019

J. Phys. D: Appl. Phys.

161

101

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Physics is the interplay of energy and matter. Energy, in the form of light, interacting with matter, principally in the solid state, underpins this topical review. The subject is developed carefully and methodically, beginning with basic definitions pertaining to terahertz detectors and terahertz radiation, then proceeding systematically to delineate characteristics of terahertz photons and terahertz detectors in more detail. In-between, the intimate connection linking terahertz sensors and terahertz sources is highlighted-an important aspect unfortunately often overlooked or ignored when terahertz detectors are discussed in isolation. At the centre of this topical review are the various physical mechanisms by which electromagnetic radiation of terahertz frequencies interacts with matter. The logic is to present first the underlying physical principles of detection before presenting the practical implementation in a specific device, rather than the other way around. A taxonomy of terahertz detectors is then proposed based on the underlying physical principles of detection. Following on from this classification, stateof-the-art terahertz detectors are surveyed and appraised; this overview constitutes the longest section of the review. Key detector parameters which inform applications are then presented and tabulated. Finally, the present state-of-the-art is anchored within the wider scientific context of historical developments and future prospects.

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“…For example, ZnTe crystal is reported suitable for terahertz (THz) device manufacture as the radiation/detection pulse has a wide frequency distribution around 3 THz under room temperature. [1,2] Besides, ZnTe crystal can be used for pure green light emitting diodes (LED) fabrication because the electroluminesence at 550 nm was DOI: 10.1002/crat.202100279 realized. [3][4][5] Moreover, ZnTe crystal is also considered as a competitive material for electro-optical modulator and mid-infrared laser device production.…”

Section: Introductionmentioning

confidence: 99%

Growth of ZnTe Semiconductor Crystal Via a Te Flux Zone Melting Method and Characterization of Its Properties

Jin

Zheng

et al. 2022

Cryst. Res. Technol.

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In this work, a kind of II;-VI group ZnTe semiconductor crystal is successfully grown using a Te flux zone melting method from Zn: Te = 3: 7 mole ratio solution. The crystal has standard F43m cubic space group and the a/b/c lattice constants are all calculated to be 6.105 Å. Energy dispersive spectroscopy analysis confirms it has quasistoichiometric ratio and the Zn/Te elements are distributed in the material homogeneously. The polished 1.0 mm thickness (110) wafer exhibits a highest ≈64.5% transmittance near 2400 nm wavelength and the bandgap E g is deduced as 2.223 eV. ZnTe crystal shows a heavy volatilization start from 910 °C and the weight losing speed is about ≈1.45% min −1 . The thermal conductivity k displays good repeatability in the cooling and heating stages, the k value is about 15.8 Wm −1 K −1 at room temperature and is deceased to 3.53 Wm −1 K −1 under 500 °C. These results would be of great reference when ZnTe crystal is used for device design and application in the future.

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Terahertz Electro-Optic Sampling in Thick ZnTe Crystals Below the Reststrahlen Band With a Broadband Femtosecond Laser

Cited by 17 publications

References 40 publications

A General Neural Network Model for Complex Refractive Index Extraction of Low-Loss Materials in the Transmission-Mode THz-TDS

A General Neural Network Model for Complex Refractive Index Extraction of Low-Loss Materials in the Transmission-Mode THz-TDS

A review of terahertz detectors

Growth of ZnTe Semiconductor Crystal Via a Te Flux Zone Melting Method and Characterization of Its Properties

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