Optically controlled dielectric properties of single-walled carbon nanotubes for terahertz wave applications

Smirnov, Serguei; Anoshkin, Ilya V.; Demchenko, Petr; Gomon, D.; Lioubtchenko, Dmitri; Khodzitsky, Mikhail K.; Oberhammer, Joachim

doi:10.1039/c8nr03740j

Cited by 29 publications

(27 citation statements)

References 33 publications

(30 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the second paper [234] they investigated composites consisting of gold nanoparticles attached to the sidewalls of SW CNTs. Smirnov et al [237] reported on the loss change upon illumination of SW CNTs composite for the THz range. [235] Shuba et al [236] proposed short-length p-doped CTNs as building blocks for high-epsilon materials in the THz range.…”

Section: Thz Response Of Carbon Nanotubesmentioning

confidence: 99%

Terahertz Spectroscopy of Nanomaterials: a Close Look at Charge‐Carrier Transport

Kužel

Němec

2019

Advanced Optical Materials

View full text Add to dashboard Cite

Transport of charges is a fundamental process in many high-tech applications including photovoltaic or optoelectronic devices, but also in more ordinary components such as unsophisticated wires and other circuitry. The development of nanotechnologies resulted in the fabrication of highly complex materials consisting of a large variety of nanosized elements, which inevitably involve a multitude of charge transport processes occurring on various time-and length-scales. Figure 1 summarizes the most common nanoelements with high application potential.For example, the electrodes employed in Grätzel solar cells [1] are composed of percolated networks of a huge number of metal oxide nanoparticles (top-left panel in Figure 1). Colloidal nanocrystals form the basis for thin film electronics and flexible electronic devices. [2] The synthetic approaches control their composition, size and electronic structure (energy levels, density of states within the bands and in the bandgap) and the charge-carrier transport. [2,3] Nanowires and nanotubes made of conventional semiconductors are quasi 1D systems combining Terahertz spectroscopy has been used for almost two decades for investigations of nanomaterials, including nanocrystals, nanoparticles, nanowires, nanotubes or 2D crystals. Its great importance stems from the fact that it is a noncontact method and, owing to its high frequency and broadband character, it is capable of characterizing charge transport properties within individual nano-objects but also among them. In addition, probing of photoinitiated ultrafast charge dynamics is possible thanks to the sub-picosecond time resolution. Despite this unprecedented potential, the interpretation of the measured terahertz conductivity spectra in many materials is still intensively debated. Herein is presented a review of the experiments performed on nanostructures of conventional semiconductors and on carbon nanomaterials (graphene and carbon nanotubes) during the past decade. The state of the art of the theoretical formalism is provided and discussed, including the intrinsic response, as well as the role of inherent heterogeneity and of the experimental conditions.

show abstract

Section: Thz Response Of Carbon Nanotubesmentioning

confidence: 99%

Terahertz Spectroscopy of Nanomaterials: a Close Look at Charge‐Carrier Transport

Kužel

Němec

2019

Advanced Optical Materials

View full text Add to dashboard Cite

show abstract

“…The complex conductivity spectra σ ν( ) of MLG ( Fig. 6) for different optical pumping intensities were extracted from transmission data using the following formula 42,60,61 in a thin-film approximation (the wavelength of THz wave is much more than the film thickness):…”

Section: Methods Characterization Of the Materials Used In Numerical mentioning

confidence: 99%

Optically tunable terahertz chiral metasurface based on multi-layered graphene

Masyukov

Vozianova

Grebenchukov

et al. 2020

Sci Rep

Self Cite

View full text Add to dashboard Cite

Active manipulation of the polarization states at terahertz frequencies is crucially helpful for polarization-sensitive spectroscopy, having significant applications such as non-contact Hall measurements, vibrational circular dichroism measurements and anisotropy imaging. the weakness of polarization manipulation provided by natural materials can be overcomed by chiral metamaterials. Chiral metamaterials have a huge potential to achieve the necessary polarization effects, hence they provide the basis for applications such as ultracompact polarization components. terahertz chiral metamaterials that allow dynamic polarization modulation of terahertz waves are of great practical interest and still challenging. Here, we show that terahertz metasurface based on the four conjugated "petal" resonators integrated with multi-layered graphene (MLG) can enable dynamically tunable chiroptical response using optical pumping. In particular, a change of ellipticity angle of 20° is observed around 0.76 THz under optical pumping by a 980 nm continuous wave (CW) laser. Furthermore, using temporal coupled-mode theory, our study also reveals that the chiroptical response of the proposed multi-layered graphene-based metasurface is strongly dependent on the influence of optical pumping on the loss parameters of resonance modes, leading to actively controllable polarization states of the transmitted terahertz waves. the present work paves the way for the realization of fundamental terahertz components capable for active polarization manipulation.

show abstract

“…The 10% increase in reactance is comparable to the measurements of a light-induced capacitance change in SWCNT layers. 15 The simulation results are shown in Fig. 2d and Fig.…”

Section: Optically-controlled Swcnt-based Phase Shiftersmentioning

confidence: 99%

“…10,11 that SWCNT layers are suitable as optically-tunable impedance surfaces for high frequency applications. 15 By illuminating the SWCNTs, their dielectric function can be tuned dynamically. The illumination power and wavelength, the thickness of the layer, and the individual tube length and diameter can all be optimized to reduce the propagation loss and maximize the tuning range for a certain frequency band.…”

Section: Introductionmentioning

confidence: 99%