Quasi-guided modes resulting from the band folding effect in a photonic crystal slab for enhanced interactions of matters with free-space radiations

• Kaili Sun,
• Yangjian Cai,
• Uriel Levy and
• Zhanghua Han

Beilstein J. Nanotechnol. 2023, 14, 322–328, doi:10.3762/bjnano.14.27

• ]. Other structures, such as diatomic [18] or dimerized [19][20] gratings, have been also investigated in recent years, but mainly with emphasis on the far-field spectrum, using one-dimensional (1D) grating structures. In addition, band folding was also employed to realize terahertz radiation from

A distributed active patch antenna model of a Josephson oscillator

• Vladimir M. Krasnov

Beilstein J. Nanotechnol. 2023, 14, 151–164, doi:10.3762/bjnano.14.16

• explains the origin of the low radiative power efficiency. Finally, I discuss the design of an optimized Josephson patch oscillator capable of reaching high efficiency and radiation power for emission into free space. Keywords: antenna theory; cavity modes; Josephson effect; terahertz radiation

• which geometrical parameters should be changed for solving the problem. The discovery of significant terahertz emission from stacked intrinsic JJs in layered high-Tc cuprates [18][19][20][21][22][23][24][25][26][27] further emphasizes the necessity of a quantitative understanding of microwave emission

• -terahertz frequencies, for which the wavelength in free space is large, λ0 ≫ b ≫ d. In this limit [36][39], where Z0 = ≃ 376.73 (Ω) is the impedance of free space. To calculate the total radiation power from both slots one has to take into account the mutual radiative conductance, G12, and the array factor

Observation of collective excitation of surface plasmon resonances in large Josephson junction arrays

• Roger Cattaneo,
• Mikhail A. Galin and
• Vladimir M. Krasnov

Beilstein J. Nanotechnol. 2022, 13, 1578–1588, doi:10.3762/bjnano.13.132

• as a common external resonator, facilitating long-range phase-locking of large junction arrays with sizes larger than the emitted wavelength. Keywords: cavity modes; Josephson junctions; synchronization mechanism; THz radiation; Introduction Terahertz sources of electromagnetic waves (EMWs) in the

• range of 0.1–10 THz are characterized by a low power efficiency [1][2][3][4][5][6]. Josephson junctions (JJs) can generate tunable terahertz radiation in a broad frequency range, from sub-terahertz in low-Tc superconductors [7][8][9], to tens of terahertz in high-Tc superconductors [10][11][12][13][14

Coherent amplification of radiation from two phase-locked Josephson junction arrays

• Mikhail A. Galin,
• Vladimir M. Krasnov,
• Ilya A. Shereshevsky,
• Nadezhda K. Vdovicheva and
• Vladislav V. Kurin

Beilstein J. Nanotechnol. 2022, 13, 1445–1457, doi:10.3762/bjnano.13.119

• voltage. Therefore, fJ can be up to about 1 THz for low-Tc JJs [1] and can reach tens of terahertz for high-Tc JJs [2][3]. Thus, a JJ has the potential to be the basis of compact, continuous-wave and tunable terahertz generators, which would facilitate solving the problem of so-called “THz gap” [4]. A

Nonlinear features of the superconductor–ferromagnet–superconductor φ₀ Josephson junction in the ferromagnetic resonance region

• Aliasghar Janalizadeh,
• Ilhom R. Rahmonov,
• Sara A. Abdelmoneim,
• Yury M. Shukrinov and
• Mohammad R. Kolahchi

Beilstein J. Nanotechnol. 2022, 13, 1155–1166, doi:10.3762/bjnano.13.97

• superconducting structures being driven far from equilibrium exhibit NDR states [32]. The NDR states plays an essential role in applications related to terahertz radiation emission [33]. A detailed explanation of the different types of negative differential resistance in Josephson junctions (i.e., N-shaped and S

Numerical study on all-optical modulation characteristics of quantum cascade lasers

• Biao Wei,
• Haijun Zhou,
• Guangxiang Li and
• Bin Tang

Beilstein J. Nanotechnol. 2022, 13, 1011–1019, doi:10.3762/bjnano.13.88

• terahertz band, it can cover most of the gas molecular-fingerprint absorption spectrum and atmospheric transmission window, and it will not damage organisms. Modulation of QCLs is an effective method of suppressing low-frequency noise and improving the signal-to-noise ratio. Various approaches to modulation

Approaching microwave photon sensitivity with Al Josephson junctions

• Andrey L. Pankratov,
• Anna V. Gordeeva,
• Leonid S. Revin,
• Dmitry A. Ladeynov,
• Anton A. Yablokov and
• Leonid S. Kuzmin

Beilstein J. Nanotechnol. 2022, 13, 582–589, doi:10.3762/bjnano.13.50

• , used before for terahertz receiver applications [27][28], in Figure 2a one can see a typical current–voltage characteristics (IVC) with the critical current close to the theoretical value [29]. Besides, a subgap structure is visible at the inverse branch of the IVC. Such a structure with peculiarities

A broadband detector based on series YBCO grain boundary Josephson junctions

• Egor I. Glushkov,
• Alexander V. Chiginev,
• Leonid S. Kuzmin and
• Leonid S. Revin

Beilstein J. Nanotechnol. 2022, 13, 325–333, doi:10.3762/bjnano.13.27

• Josephson detector was applied to detect a small signal from a BiSrCaCuO mesa structure at an operating temperature of 25 K [11]. A HTSC JJ has also analyzed pulsed terahertz radiation from quantum cascade lasers located in the same cryogenic environment at 50 K [12]. Another important advantage of HTSCs is

• a wide frequency range from tens of gigahertz to several terahertz [13][14], which exceeds the gap limitation of low-Tc detectors. So, in [12] the spectrum of a quantum cascade laser emission has been recovered by an YBaCuO detector at a central frequency around 2.2 THz. However, for some

Design aspects of Bi₂Sr₂CaCu₂O_8+δ THz sources: optimization of thermal and radiative properties

• Mikhail M. Krasnov,
• Natalia D. Novikova,
• Roger Cattaneo,
• Alexey A. Kalenyuk and
• Vladimir M. Krasnov

Beilstein J. Nanotechnol. 2021, 12, 1392–1403, doi:10.3762/bjnano.12.103

• Center, SE-10691 Stockholm, Sweden Institute of Metal Physics of National Academy of Sciences of Ukraine, 03142 Kyiv, Ukraine Kyiv Academic University, 03142 Kyiv, Ukraine 10.3762/bjnano.12.103 Abstract Impedance matching and heat management are important factors influencing the performance of terahertz

• crystal and the electrode leads to appearance of a large parasitic capacitance, which shunts terahertz emission and prevents impedance matching with open space. The overlap is avoided in whisker-based devices. Furthermore, the whisker and the electrodes form a turnstile (crossed-dipole) antenna

• junctions; numerical modelling; terahertz sources; Introduction Tunable, monochromatic, continuous-wave (CW), compact, and power-efficient terahertz (THz) sources of electromagnetic waves (EMW) are required for a broad variety of applications [1]. However, the key obstacle, colloquially known as “the THz

Nonmonotonous temperature dependence of Shapiro steps in YBCO grain boundary junctions

• Leonid S. Revin,
• Dmitriy V. Masterov,
• Alexey E. Parafin,
• Sergey A. Pavlov and
• Andrey L. Pankratov

Beilstein J. Nanotechnol. 2021, 12, 1279–1285, doi:10.3762/bjnano.12.95

• . For applied tasks of terahertz imaging [47], mixing [36], and Hilbert-transform spectral analysis [13] it is not possible to vary the incident power over a wide range. The power level is set there by losses, mismatch, and power absorption by the samples under study. Moreover, in applied problems one

Recent progress in magnetic applications for micro- and nanorobots

• Ke Xu,
• Shuang Xu and
• Fanan Wei

Beilstein J. Nanotechnol. 2021, 12, 744–755, doi:10.3762/bjnano.12.58

• with different magnetisms with applications in, for example, energy-saving logic, sensors, environmental remediation, and data storage [52]. Chen et al. [53] studied compensated magnetic heterostructures containing ferrimagnetic CoGd alloys and antiferromagnetic IrMn layers. The terahertz emission from

• the ferrimagnetic nanoparticles showed good temperature stability. The proposed new terahertz technology can be better applied to many fields such as chemical composition analysis and integrated circuit analysis. Hence, it can be seen that magnetic MNRs are widely used. From controlling individual

A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

• Josephson junctions [39]. Similar multi-step irradiation routines have been used to fabricate SQUID micromagnetometers entirely using helium ion irradiation [40][41][42][43], nano-SQUID-based transimpedance amplifiers [44], and Josephson junctions in the superconducting bridge of spiral terahertz antenna

Determining amplitude and tilt of a lateral force microscopy sensor

• Oliver Gretz,
• Alfred J. Weymouth,
• Thomas Holzmann,
• Korbinian Pürckhauer and
• Franz J. Giessibl

Beilstein J. Nanotechnol. 2021, 12, 517–524, doi:10.3762/bjnano.12.42

• the terahertz range [29][30] and is not excited by the tip, which oscillates in the kilohertz range. Figure 7a shows the I(x, z) current map without oscillation. In the inset, an STM image of a CO molecule with a CO tip is shown [31]. The red solid curve in Figure 7b shows the current profile ⟨I

Microwave photon detection by an Al Josephson junction

• Leonid S. Revin,
• Andrey L. Pankratov,
• Anna V. Gordeeva,
• Anton A. Yablokov,
• Igor V. Rakut,
• Victor O. Zbrozhek and
• Leonid S. Kuzmin

Beilstein J. Nanotechnol. 2020, 11, 960–965, doi:10.3762/bjnano.11.80

• counters in the gigahertz frequency range. Such devices are in demand in several areas, such as the search for axions, the alleged particles of dark matter [1][2][3][4] and quantum computing [5]. Commercially available single-photon detectors operate at frequencies of hundreds of terahertz and higher [6][7

Nanoscale optical and structural characterisation of silk

• Meguya Ryu,
• Reo Honda,
• Adrian Cernescu,
• Arturas Vailionis,
• Armandas Balčytis,
• Jitraporn Vongsvivut,
• Jing-Liang Li,
• Denver P. Linklater,
• Elena P. Ivanova,
• Vygantas Mizeikis,
• Mark J. Tobin,
• Junko Morikawa and
• Saulius Juodkazis

Beilstein J. Nanotechnol. 2019, 10, 922–929, doi:10.3762/bjnano.10.93

• properties of a material are interrelated. By using a wide spectrum of electromagnetic waves from visible light to terahertz radiation, it is possible to gain insights into complex hierarchical structures of composite materials. For materials with strong structural anisotropy, defined by the molecular

Coexisting spin and Rabi oscillations at intermediate time regimes in electron transport through a photon cavity

• Vidar Gudmundsson,
• Hallmann Gestsson,
• Nzar Rauf Abdullah,
• Chi-Shung Tang,
• Andrei Manolescu and
• Valeriu Moldoveanu

Beilstein J. Nanotechnol. 2019, 10, 606–616, doi:10.3762/bjnano.10.61

• combining nanoconductors and metallic reservoirs [12]. Eventually, this effort might lead to the evolution of devices active in the challenging terahertz regime, which would open up novel possibilities [12]. This has led us to consider particular aspects of the electron–photon interaction on quantum

• . The challenging terahertz or FIR regime for semiconducting QED circuits offers interesting possibilities for fundamental research into the electron–photon interactions and devices with new potentials. (Upper) Schematic for a short quantum wire in a 3D photon cavity coupled to semi-infinite external

Nanoantenna structures for the detection of phonons in nanocrystals

• Alexander G. Milekhin,
• Sergei A. Kuznetsov,
• Ilya A. Milekhin,
• Larisa L. Sveshnikova,
• Tatyana A. Duda,
• Ekaterina E. Rodyakina,
• Alexander V. Latyshev,
• Volodymyr M. Dzhagan and
• Dietrich R. T. Zahn

Beilstein J. Nanotechnol. 2018, 9, 2646–2656, doi:10.3762/bjnano.9.246

• transverse modes, respectively). The longitudinal mode has a LSPR energy in the IR spectral range and is utilized for SEIRA experiments. This energy can be gradually tuned from near- to far-infrared (or terahertz) via increasing the nanoantenna length [14][15]. The transverse mode has a much shorter

• ), while the antenna length varied in the range of 7–31 µm. The optimal values of the latter were determined numerically using 3D full-wave simulations in the ANSYS Electromagnetics Suite R18 software [32] to adjust the plasmon resonance to a specific wavelength in the far-infrared (terahertz) spectral

Enhancement of X-ray emission from nanocolloidal gold suspensions under double-pulse excitation

• Wei-Hung Hsu,
• Frances Camille P. Masim,
• Armandas Balčytis,
• Hsin-Hui Huang,
• Tetsu Yonezawa,
• Aleksandr A. Kuchmizhak,
• Saulius Juodkazis and
• Koji Hatanaka

Beilstein J. Nanotechnol. 2018, 9, 2609–2617, doi:10.3762/bjnano.9.242

• laser and plasmonic nanoparticles will contribute to a broad field of applications ranging from pulsed X-ray generation to energetic particle sources [14] or terahertz wave emission from aqueous solutions [16]. In recent experimental studies, intense fs-laser excitation of plasmonic gold nanoparticles

• -laser pulses for terahertz-wave emission from water flow were reported [51], while terahertz emission from various solutions under broad focusing was already known [52]. Simultaneous emission of X-ray and terahertz waves from gas clusters in vacuum [53][54], Al-coated glass substrates in vacuum [54], or

• a distilled water flow in air under double-pulse excitation [16] were independently reported. A simultaneous emission of X-ray and terahertz wave radiation is highly expected for novel pump–probe experiments [55]. The knowledge obtained in this paper will contribute to further advancements in this

Influence of the thickness of an antiferromagnetic IrMn layer on the static and dynamic magnetization of weakly coupled CoFeB/IrMn/CoFeB trilayers

• Deepika Jhajhria,
• Dinesh K. Pandya and
• Sujeet Chaudhary

Beilstein J. Nanotechnol. 2018, 9, 2198–2208, doi:10.3762/bjnano.9.206

• and AF magnons at the FM/AF interface since the energy of a uniform precession magnon (wave vector k = 0) is too small to excite any AF magnons (frequency in the terahertz range). According to theoretical studies, the coupling between FM magnons and AF magnons across the interface takes place via at

Light–Matter interactions on the nanoscale

• Mohsen Rahmani and
• Chennupati Jagadish

Beilstein J. Nanotechnol. 2018, 9, 2125–2127, doi:10.3762/bjnano.9.201

• devices, as well as biomedical engineering [3][4]. Subsequently, with advances in photolithography, the microscale structure of materials began to attract much research interest due to their unique capability to interact with an applied electromagnetic wave in the radio frequency and terahertz regions [5

Cathodoluminescence as a probe of the optical properties of resonant apertures in a metallic film

• Kalpana Singh,
• Evgeniy Panchenko,
• Babak Nasr,
• Amelia Liu,
• Lukas Wesemann,
• Timothy J. Davis and
• Ann Roberts

Beilstein J. Nanotechnol. 2018, 9, 1491–1500, doi:10.3762/bjnano.9.140

• resonances in the terahertz regime has been demonstrated. As is the case with nanoparticles, nanoholes play an important role as basic building blocks in a range of nanophotonic devices, including colour filters [21][22][23][24] and compact polarizers [25], exploiting resonant properties of the subwavelength

Tailoring polarization and magnetization of absorbing terahertz metamaterials using a cut-wire sandwich structure

• Hadi Teguh Yudistira,
• Shuo Liu,
• Tie Jun Cui and
• Han Zhang

Beilstein J. Nanotechnol. 2018, 9, 1437–1447, doi:10.3762/bjnano.9.136

• could be matched to that of free space while generating a large imaginary part in the refractive index. This work characterizes the absorption performance of such sandwich structures in the terahertz regime. This mechanism could be further extended to other metamaterial devices in the terahertz and

• other frequency ranges because polarization and magnetization can now be selectively controlled in a straightforward manner. Keywords: absorber; cut-wire; metamaterial; terahertz; Introduction The terahertz spectrum is located between the infrared and microwave spectrum. This part of the spectrum has

• unique properties, such as being non-ionizing and subject to considerably less Rayleigh scattering than the visible or infrared spectrum [1]. The terahertz spectrum has been widely used in research fields such as medical imaging [1][2][3] and security applications [4]. Optical [5][6][7] and microwave

Non-equilibrium electron transport induced by terahertz radiation in the topological and trivial phases of Hg_1−xCd_xTe

• Alexandra V. Galeeva,
• Alexey I. Artamkin,
• Alexey S. Kazakov,
• Sergey N. Danilov,
• Sergey A. Dvoretskiy,
• Nikolay N. Mikhailov,
• Ludmila I. Ryabova and
• Dmitry R. Khokhlov

Beilstein J. Nanotechnol. 2018, 9, 1035–1039, doi:10.3762/bjnano.9.96

• . 53, 119991 Moscow, Russia 10.3762/bjnano.9.96 Abstract Terahertz photoconductivity in heterostructures based on n-type Hg1−xCdxTe epitaxial films both in the topological phase (x < 0.16, inverted band structure, zero band gap) and the trivial state (x > 0.16, normal band structure) has been studied

• and 2D topological Dirac states coexisting in a smooth topological heterojunction. Keywords: terahertz radiation; topological insulator; photoconductivity; Findings Discovery of theoretically predicted quantum spin Hall effect states in HgTe quantum wells [1][2] has initiated extensive studies of

• carrier transport. Laser terahertz probing is known to be a powerful tool that may provide an insight into the electron dynamics in semiconductors, particularly, in topological insulators [9][10][11]. Study of non-equilibrium processes in Hg1−xCdxTe in the terahertz spectral range is additionally

Nanoantenna-assisted plasmonic enhancement of IR absorption of vibrational modes of organic molecules

• Alexander G. Milekhin,
• Olga Cherkasova,
• Sergei A. Kuznetsov,
• Ilya A. Milekhin,
• Ekatherina E. Rodyakina,
• Alexander V. Latyshev,
• Sreetama Banerjee,
• Georgeta Salvan and
• Dietrich R. T. Zahn

Beilstein J. Nanotechnol. 2017, 8, 975–981, doi:10.3762/bjnano.8.99

• , corresponding to only 145 molecules per antenna [20]. A similar approach is used for the terahertz (or far-IR) spectral range for which special nanoscale slot-antenna arrays were designed to determine glucose and fructose in solutions, including market beverages [21]. Terahertz transmittance measurements were

Anodization-based process for the fabrication of all niobium nitride Josephson junction structures

• Massimiliano Lucci,
• Ivano Ottaviani,
• Matteo Cirillo,
• Fabio De Matteis,
• Roberto Francini,
• Vittorio Merlo and
• Ivan Davoli

Beilstein J. Nanotechnol. 2017, 8, 539–546, doi:10.3762/bjnano.8.58

• high critical temperature and energy gap of the order, respectively, of 16 K and 2.5 mV [4][5][6][7][8]. The transition temperature is appealing because of the progress achieved in closed-cycle refrigeration, while the value of the gap is stimulating for engineering devices in the terahertz range