Powerful and Tunable THz Emitters Based on the Fe/Pt Magnetic Heterostructure

Yang, Dewang; Liang, Jianhui; Zhou, Chao; Sun, Lu; Zheng, Ronger; Luo, Sheng‐Nian; Wu, Y. Z.; Qi, J.

doi:10.1002/adom.201600270

Cited by 185 publications

(207 citation statements)

References 37 publications

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“…This can be attributed to the magnetic shape anisotropy induced by demagnetitzation parameter of the subwavelength stripe structure . As previous work demonstrated, the THz amplitude has a strong proportional correlation with the magnetic moment . However, in sharp contrast, the maximum peak‐to‐peak values of THz signal are obtained at θ = 0°, 180°, and 360°, at which the magnitudes of M @2000 Oe are minimum.…”

mentioning

confidence: 83%

“…It has been well known that metamaterial can be used to effectively control the THz wave propagation, even as a broadband THz source . By structuring a spintronic THz source in a grating type, Yang et al observed a modification of the emitted THz waveform as the THz emitter is rotated about the surface normal . However, the role of microstructure on the actual magnetization and on the absorption of pump pulses of the spintronic THz emitter remains unclear.…”

mentioning

confidence: 99%

“…We now turn to the other possible physical mechanism for the θ ‐dependent THz radiation, which is the charge current confinement effect . As shown in the geometry in Figure d, in the case of θ = 90°, the spatial separation of the photoinduced positive and negative charges accumulates and then creates a nonequilibrium electric potential U ( t ) at the edge of the stripe structure.…”

mentioning

confidence: 99%

“…As shown in the geometry in Figure d, in the case of θ = 90°, the spatial separation of the photoinduced positive and negative charges accumulates and then creates a nonequilibrium electric potential U ( t ) at the edge of the stripe structure. Such transient U ( t ) produces an opposite built‐in electric field, E b ( t )

= \frac{U false(t false)}{ε L_{eff}}

, which induces a back‐flowing transient current j b ( t ) simultaneously in the stripe structure . It is well known that

E_{THz} (ω) \propto \frac{\partial j_{eff} false(t false)}{\partial t}

, where

j_{eff} (t) = j_{normalc} (t) + j_{normalb} (t)

.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Terahertz Radiation Modulated by Confinement of Picosecond Current Based on Patterned Ferromagnetic Heterostructures

Jin

Zhang

Zhu

et al. 2019

Physica Rapid Research Ltrs

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The ultrashort laser excitation of nonmagnetic/ferromagnetic/nonmagnetic (NM/FM/NM) heterostructures is intensively studied as a terahertz (THz) emitter. Herein, the combined spintronic and photonic ultrathin metal heterostructures are exploited to realize actively modulated THz radiation. It is demonstrated that the THz radiation can be mediated coherently through the charge current induced by the inverse spin Hall effect (ISHE) and the built‐in transient current quasi‐simultaneously created within the striped NM/FM/NM heterostructures. The waveforms of THz radiation can be shaped by the charge current confinement effect, including the amplitude modulation and the center‐frequency shift. These findings can be utilized for device‐oriented opto‐spintronics and also extend the established THz emitter to THz modulator.

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mentioning

confidence: 83%

mentioning

confidence: 99%

mentioning

confidence: 99%

= \frac{U false(t false)}{ε L_{eff}}

, which induces a back‐flowing transient current j b ( t ) simultaneously in the stripe structure . It is well known that

E_{THz} (ω) \propto \frac{\partial j_{eff} false(t false)}{\partial t}

, where

j_{eff} (t) = j_{normalc} (t) + j_{normalb} (t)

.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Terahertz Radiation Modulated by Confinement of Picosecond Current Based on Patterned Ferromagnetic Heterostructures

Jin

Zhang

Zhu

et al. 2019

Physica Rapid Research Ltrs

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“…14 Recently, THz sources based on metallic spintronic heterostructures were shown to be a n e w a n d p r o m i s i n g c l a s s o f T H z emitters. 15,16,17,18,19,20,21 When excited with 10 fs nanojoule-class laser pulses from an oscillator, a gapless spectrum from 1 to 30 THz and a conversion efficiency comparable to or even better than standard oscillator-based THz emitters were achieved. 22 Advantages of this emitter concept are ease-of-use, stability and a collinear geometry.…”

mentioning

confidence: 99%

Ultrabroadband single-cycle terahertz pulses with peak fields of 300 kV cm−1 from a metallic spintronic emitter

Seifert

Jaiswal

Sajadi

et al. 2017

Applied Physics Letters

179

128

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To explore the capabilities of metallic spintronic thin-film stacks as a source of intense and broadband terahertz electromagnetic fields, we excite a W/CoFeB/Pt trilayer on a large-area glass substrate (diameter of 7.5 cm) by a femtosecond laser pulse (energy 5.5 mJ, duration 40 fs, wavelength 800 nm). After focusing, the emitted terahertz pulse is measured to have a duration of 230 fs, a peak field of 300 kV cm -1 and an energy of 5 nJ. In particular, the waveform exhibits a gapless spectrum extending from 1 to 10 THz at 10% of amplitude maximum, thereby facilitating nonlinear control over matter in this difficult-to-reach frequency range and on the sub-picosecond time scale.Terahertz (THz) pulses covering the range from 1 to 20 THz are useful resonant probes of numerous low-energy excitations in all phases of matter. Completely new research avenues open up when THz pulses are used to drive rather than probe materials resonances.

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Ultrafast Spin‐to‐Charge Conversion at the Surface of Topological Insulator Thin Films

et al. 2018

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Strong spin–orbit coupling, resulting in the formation of spin‐momentum‐locked surface states, endows topological insulators with superior spin‐to‐charge conversion characteristics, though the dynamics that govern it have remained elusive. Here, an all‐optical method is presented, which enables unprecedented tracking of the ultrafast dynamics of spin‐to‐charge conversion in a prototypical topological insulator Bi2Se3/ferromagnetic Co heterostructure, down to the sub‐picosecond timescale. Compared to pure Bi2Se3 or Co, a giant terahertz emission is observed in the heterostructure that originates from spin‐to‐charge conversion, in which the topological surface states play a crucial role. A 0.12 ps timescale is identified that sets a technological speed limit of spin‐to‐charge conversion processes in topological insulators. In addition, it is shown that the spin‐to‐charge conversion efficiency is temperature independent in Bi2Se3 as expected from the nature of the surface states, paving the way for designing next‐generation high‐speed optospintronic devices based on topological insulators at room temperature.

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Powerful and Tunable THz Emitters Based on the Fe/Pt Magnetic Heterostructure

Cited by 185 publications

References 37 publications

Terahertz Radiation Modulated by Confinement of Picosecond Current Based on Patterned Ferromagnetic Heterostructures

Terahertz Radiation Modulated by Confinement of Picosecond Current Based on Patterned Ferromagnetic Heterostructures

Ultrabroadband single-cycle terahertz pulses with peak fields of 300 kV cm−1 from a metallic spintronic emitter

Ultrafast Spin‐to‐Charge Conversion at the Surface of Topological Insulator Thin Films

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