THz emitters based on the photo-Dember effect

Apostolopoulos, Vasilis; Barnes, M. E.

doi:10.1088/0022-3727/47/37/374002

Cited by 89 publications

(51 citation statements)

References 127 publications

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“…We have introduced them phenomenologically by an exponential decay with time constant . Backflow of electrons is diffusive37 and ignored on the short timescales considered here. Finally, the convolution (denoted by ) with the pump intensity envelope I p ( t ) (normalized to unity) accounts for the shape of the pump pulse, resulting in a current with the typical temporal shape shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Ultrafast photocurrents at the surface of the three-dimensional topological insulator Bi2Se3

Braun¹,

Mußler²,

Hruban³

et al. 2016

Nat Commun

185

176

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Three-dimensional topological insulators are fascinating materials with insulating bulk yet metallic surfaces that host highly mobile charge carriers with locked spin and momentum. Remarkably, surface currents with tunable direction and magnitude can be launched with tailored light beams. To better understand the underlying mechanisms, the current dynamics need to be resolved on the timescale of elementary scattering events (∼10 fs). Here, we excite and measure photocurrents in the model topological insulator Bi2Se3 with a time resolution of 20 fs by sampling the concomitantly emitted broadband terahertz (THz) electromagnetic field from 0.3 to 40 THz. Strikingly, the surface current response is dominated by an ultrafast charge transfer along the Se–Bi bonds. In contrast, photon-helicity-dependent photocurrents are found to be orders of magnitude smaller than expected from generation scenarios based on asymmetric depopulation of the Dirac cone. Our findings are of direct relevance for broadband optoelectronic devices based on topological-insulator surface currents.

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Section: Resultsmentioning

confidence: 99%

Ultrafast photocurrents at the surface of the three-dimensional topological insulator Bi2Se3

Braun¹,

Mußler²,

Hruban³

et al. 2016

Nat Commun

185

176

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“…Excitation of BiVO 4 thin films deposited on a glass substrate using femtosecond laser pulses does not produce any measurable THz emission. This excludes the possibility of THz emission due to a surface depletion field or the surface photo-Dember effect [29][30][31][32]. We propose a new generation mechanism based on the longitudinal photo-Dember effect.…”

Section: Resultsmentioning

confidence: 92%

Investigation of Terahertz Emission from BiVO4/Au Thin Film Interface

Kumar

Abdi

Trześniewski

et al. 2015

J Infrared Milli Terahz Waves

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“…Таким образом, фотопроводящий материал на основе In 0.38 Ga 0.62 As имеет высокую эффективность оптико-ТГц конверсии и широкий спектр ТГц излучения, что поз-волит в дальнейшем использовать данный материал для изготовления ФА и фотопроводящих источников на основе латерального фотоэффекта Дембера [20,29].…”

Section: рисunclassified

Генерация терагерцового излучения при облучении фемтосекундными лазерными импульсами In-=SUB=-0.38-=/SUB=-Ga-=SUB=-0.62-=/SUB=-As, выращенного на подложке GaAs с метаморфным буферным слоем

Пономарев¹,

Хабибуллин²,

Ячменев³

et al. 2017

Физика И Техника Полупроводников

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Приведены результаты исследований генерации терагерцового (ТГц) излучения с помощью спектроскопии с временным разрешением в структуре с фотопроводящим слоем In 0.38 Ga 0.62 As. Исследуемая структура, выращенная методом молекулярно-лучевой эпитаксии на подложке GaAs с помощью метаморфного буфера, позволяет генерировать ТГц излучение с широким спектром частот (вплоть до 6 ТГц). Это связано с дополнительным вкладом фотовольтаического эффекта Дембера в генерацию ТГц излучения. Измеренная эффективность оптико-терагерцового преобразования в такой структуре составляет ∼ 10 −5 при достаточно малом оптическом флюенсе ∼ 40 мкДж/см 2 , что почти на два порядка выше, чем в " низкотемператур-ном" GaAs.

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THz emitters based on the photo-Dember effect

Cited by 89 publications

References 127 publications

Ultrafast photocurrents at the surface of the three-dimensional topological insulator Bi2Se3

Ultrafast photocurrents at the surface of the three-dimensional topological insulator Bi2Se3

Investigation of Terahertz Emission from BiVO4/Au Thin Film Interface

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