Highly sensitive electro-optic sampling of terahertz waves using field enhancement in a tapered waveguide structure

Tsuzuki, Seiji; Takeshima, Daiki; Sakon, Tomoya; Kinoshita, Tetsuya; Nagase, Takeshi; Kurihara, Kazuyoshi; Yamamoto, Kohji; Kuwashima, Fumiyoshi; Furuya, Takashi; Estacio, Elmer; Kawase, Kodo; Бакунов, М. И.; Tani, Masahiko

doi:10.7567/apex.7.112401

Cited by 18 publications

(4 citation statements)

References 21 publications

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“…[85,86] A similar scheme utilized LiNbO 3 , where Cherenkov-type THz radiation was coupled into a parallel-plate waveguide, subsequently sampled using an optical probe pulse propagating as the fundamental dielectric slab waveguide mode. [87,88] Due to the realm of EO sampling waveguiding schemes being largely unexplored, we envision rapid developments to be observed within this area.…”

Section: Outlook and Discussion On Prospectsmentioning

confidence: 99%

Nonlinear Photonic Waveguides: A Versatile Platform for Terahertz Radiation Generation (a Review)

Carnio

Moutanabbir

Elezzabi

2023

Laser & Photonics Reviews

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Continued development in the areas of communication, security, medicine, and safety is calling for terahertz‐wave technologies to evolve beyond laboratory research and into the realm of real‐world applications. Due to the compatibility of waveguides with on‐chip fabrication techniques and their ability to realize a small footprint, such structures provide a unique opportunity to achieve terahertz radiation generation in an on‐chip arrangement, ideal for practical applications requiring terahertz electric fields. This review considers waveguiding arrangements that produce terahertz radiation using the nonlinear frequency‐conversion techniques of optical rectification and difference frequency generation. The investigated terahertz radiation waveguiding sources are categorized into three different classes: those that confine and guide both the excitation electric fields and the generated terahertz radiation, those that confine and guide the excitation electric fields but not the generated terahertz radiation, and those that confine and guide the generated terahertz radiation but not the excitation electric fields. Various types of waveguides are surveyed from each category, including dielectric waveguides, metallic waveguides, photonic crystal waveguides, poled waveguides, and multiple waveguides embedded within one another. This review provides a detailed overview of state‐of‐the‐art terahertz radiation waveguide sources, with the intent of aiding in the continuing development of such sources.

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Section: Outlook and Discussion On Prospectsmentioning

confidence: 99%

Nonlinear Photonic Waveguides: A Versatile Platform for Terahertz Radiation Generation (a Review)

Carnio

Moutanabbir

Elezzabi

2023

Laser & Photonics Reviews

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“…A NIR laser pulse passing through the crystal undergoes a polarization rotation in response to this change in refractive index and this polarization rotation can be detected by using a balanced bridge photodiode. The efficiency of electro-optic sampling for THz detection depends on a number of factors including the absorption coefficient of the electro-optic crystal, the velocity mismatch between laser pulse and terahertz beam, and the spatial overlap of the terahertz beam and optical pulse 52 . In the quest to solve the problem of velocity mismatch between terahertz beam and laser pulse, Wu et al used electro-optic crystals like ZnTe and GaP that have a smaller absorption coefficient 51 .…”

Section: Electro-optical Samplingmentioning

confidence: 99%

Principles of spintronic THz emitters

Wu,

Ameyaw,

Doty

et al. 2021

Preprint

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Significant progress has been made in answering fundamental questions about how and, more importantly, on what time scales interactions between electrons, spins, and phonons occur in solid state materials. These complex interactions are leading to the first real applications of terahertz (THz) spintronics: THz emitters that can compete with traditional THz sources and provide additional functionalities enabled by the spin degree of freedom. This tutorial article is intended to provide the background necessary to understand, use, and improve THz spintronic emitters. A particular focus is the introduction of the physical effects that underlie the operation of spintronic THz emitters. These effects were, for the most part, first discovered through traditional spin-transport and spintronic studies. We therefore begin with a review of the historical background and current theoretical understanding of ultrafast spin physics that has been developed over the past twenty-five years. We then discuss standard experimental techniques for the characterization of spintronic THz emitters and -more broadly -ultrafast magnetic phenomena. We next present the principles and methods of the synthesis and fabrication of various types of spintronic THz emitters. Finally, we review recent developments in this exciting field including the integration of novel material platforms such as topological insulators as well as antiferromagnets and materials with unconventional spin textures.

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“…28,29) A significant improvement in the detection efficiency had been achieved due to a concentration of the terahertz field in the TPPWG. 30) Noncollinear terahertz generation in a 600 μm thick layer of GaAs loaded into a TPPWG has also been demonstrated. 28) In this paper, the effect of focusing conditions on the noncollinear terahertz generation efficiency and bandwidth is studied both for a thin (100 μm) layer of GaAs loaded into a TPPWG and for a bulk GaAs crystal.…”

Section: Introductionmentioning

confidence: 96%

Terahertz generation in a thin GaAs slab in a tapered parallel plate waveguide by femtosecond laser excitation at 1560 nm

Furuya¹,

Muldera²,

Бакунов³

et al. 2021

Jpn. J. Appl. Phys.

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A comparative experimental study of terahertz generation by optical rectification of femtosecond laser pulses with a wavelength of 1560 nm in a 100 μm thick slab of GaAs sandwiched between the walls of a tapered metallic waveguide and in a bulk GaAs crystal has been performed. In both cases, the velocity mismatch between the optical and terahertz beams propagating in GaAs was overcome by using the Cherenkov phase-matching method. The dependence of the terahertz time-domain signal amplitude, spectral bandwidth, and dynamic range on the focusing conditions were measured and compared. For both samples, the most efficient generation was observed for the 50 mm focal length lens. A significant improvement in the directionality of the terahertz emission from the thin GaAs slab due to the tapered waveguide was predicted by FDTD simulations and this was also confirmed experimentally.

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Highly sensitive electro-optic sampling of terahertz waves using field enhancement in a tapered waveguide structure

Cited by 18 publications

References 21 publications

Nonlinear Photonic Waveguides: A Versatile Platform for Terahertz Radiation Generation (a Review)

Nonlinear Photonic Waveguides: A Versatile Platform for Terahertz Radiation Generation (a Review)

Principles of spintronic THz emitters

Terahertz generation in a thin GaAs slab in a tapered parallel plate waveguide by femtosecond laser excitation at 1560 nm

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