Terahertz optical rectification from 〈110〉 zinc-blende crystals

Rice, Anthony D.; Jin, Yanping; F., X.; Zhang, X.‐C.; Bliss, D.; Larkin, John J.; Alexander, M.

doi:10.1063/1.111922

Cited by 399 publications

(229 citation statements)

References 12 publications

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“…Bulk polarization is not required; only inversion symmetry must be broken. Shift currents have been investigated experimentally [19,[27][28][29][30][31][32][33][34], analytically [20,23,[35][36][37], and computationally, although only for a few nonpolar materials [23][24][25]. Perturbative analysis treating the electromagnetic field classically yields the shift current expression [20,23] J q ¼ rsq E r E s rsq ð!Þ ¼ e e m@!…”

Section: First Principles Calculation Of the Shift Current Photovoltamentioning

confidence: 99%

First Principles Calculation of the Shift Current Photovoltaic Effect in Ferroelectrics

2012

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We calculate the bulk photovoltaic response of the ferroelectrics BaTiO 3 and PbTiO 3 from first principles by applying "shift current" theory to the electronic structure from density functional theory. The first principles results for BaTiO 3 reproduce eperimental photocurrent direction and magnitude as a function of light frequency, as well as the dependence of current on light polarization, demonstrating that shift current is the dominant mechanism of the bulk photovoltaic effect in BaTiO 3 . Additionally, we analyze the relationship between response and material properties in detail. The photocurrent does not depend simply or strongly on the magnitude of material polarization, as has been previously assumed; instead, electronic states with delocalized, covalent bonding that is highly asymmetric along the current direction are required for strong shift current enhancements. The complexity of the response dependence on both external and material parameters suggests applications not only in solar energy conversion, but to photocatalysis and sensor and switch type devices as well.

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Section: First Principles Calculation Of the Shift Current Photovoltamentioning

confidence: 99%

First Principles Calculation of the Shift Current Photovoltaic Effect in Ferroelectrics

2012

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“…Sources made from solids usually consist of semiconducting or insulating structures with naturally or artificially broken inversion symmetry. When the incident photon energy is below the semiconductor band gap, optical rectification causes a charge displacement that follows the intensity envelope of the incident pump pulse 9,10,11,12,13,14,15,16,17 . For above-band-gap excitation, the response is dominated by a photocurrent 18,19,20,21,22,23,24 with a temporally step-like onset and, thus, generally smaller bandwidth than optical rectification 9 .…”

Section: Introductionmentioning

confidence: 99%

Efficient metallic spintronic emitters of ultrabroadband terahertz radiation

Seifert¹,

Jaiswal²,

Martens³

et al. 2016

Nature Photon

727

802

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Terahertz electromagnetic radiation is extremely useful for numerous applications such as imaging and spectroscopy. Therefore, it is highly desirable to have an efficient table-top emitter covering the 1-to-30-THz window whilst being driven by a low-cost, low-power femtosecond laser oscillator. So far, all solid-state emitters solely exploit physics related to the electron charge and deliver emission spectra with substantial gaps. Here, we take advantage of the electron spin to realize a conceptually new terahertz source which relies on tailored fundamental spintronic and photonic phenomena in magnetic metal multilayers: ultrafast photo-induced spin currents, the inverse spin-Hall effect and a broadband Fabry-Pérot resonance. Guided by an analytical model, such spintronic route offers unique possibilities for systematic optimization. We find that a 5.8-nm-thick W/CoFeB/Pt trilayer generates ultrashort pulses fully covering the 1-to-30-THz range. Our novel source outperforms laser-oscillatordriven emitters such as ZnTe(110) crystals in terms of bandwidth, terahertz-field amplitude, flexibility, scalability and cost. IntroductionThe terahertz (THz) window, loosely defined as the frequency range from 0.3 to 30 THz in the electromagnetic spectrum, is located between the realms of electronics and optics 1,2 . As this region coincides with many fundamental resonances of materials, THz radiation enables very selective spectroscopic insights into all phases of matter with high temporal 3,4 and spatial 5,6,7,8 resolution. Consequently, numerous applications in basic research 3,4 , imaging 5 and quality control 8 have emerged.To fully exploit the potential of THz radiation, energy-efficient and low-cost sources of ultrashort THz pulses are required. Most broadband table-top emitters are driven by femtosecond laser pulses that generate the required THz charge current by appropriately mixing the various optical frequencies 9,10 . Sources made from solids usually consist of semiconducting or insulating structures with naturally or artificially broken inversion symmetry. When the incident photon energy is below the semiconductor band gap, optical rectification causes a charge displacement that follows the intensity envelope of the incident pump pulse 9,10,11,12,13,14,15,16,17 . For above-band-gap excitation, the response is dominated by a photocurrent 18,19,20,21,22,23,24 with a temporally step-like onset and, thus, generally smaller bandwidth than optical rectification 9 . Apart from rare exceptions 14 , however, most semiconductors used are polar 1,2,12,13,15,16,17,21,22 and strongly attenuate THz radiation around optical phonon resonances, thereby preventing emission in the so-called Reststrahlen band located between ~1 and 15 THz.The so far most promising sources covering the full THz window are photocurrents in transient gas plasmas 9,10,25,26,27,28,29 . The downside of this appealing approach is that the underlying ionization process usually requires amplified laser pulses with high threshold energies on the order of 0....

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“…6 In fact, if the wafer is diced ͑or cleaved͒ along the proper axis one may reveal the ͑110͒ plane, which has been previously exploited for THz generation via optical rectification. 7,8 The spectra in Fig. 3 show that both the PPT and F-chip transmitters are capable of producing similar bandwidth signals at zero bias.…”

Section: School Of Electrical and Computer Engineeringmentioning

confidence: 99%

Parallel plate THz transmitter

Coleman

Grischkowsky

2004

Applied Physics Letters

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A THz transmitter that directly excites the guided wave modes of a dielectric filled parallel plate waveguide is demonstrated. When coupled to free space, the transmitter yields a large peak time-domain THz signal. The device yields significant signal amplitudes with varying output spectra with and without a bias field applied. This transmitter provides powerful direct excitation of guided wave modes and is the next step toward an integrated guided wave transverse-electromagnetic mode THz bandwidth device.

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Terahertz optical rectification from 〈110〉 zinc-blende crystals

Cited by 399 publications

References 12 publications

First Principles Calculation of the Shift Current Photovoltaic Effect in Ferroelectrics

First Principles Calculation of the Shift Current Photovoltaic Effect in Ferroelectrics

Efficient metallic spintronic emitters of ultrabroadband terahertz radiation

Parallel plate THz transmitter

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