Studying of dielectric properties of polymers in the terahertz frequency range

Fedulova, Elena; Nazarov, Maxim; Angeluts, A. A.; Китай, М. С.; Соколов, В. И.; Shkurinov, Alexander P.

doi:10.1117/12.923855

Cited by 60 publications

(35 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The n(ω) spectra of both neat copolymers, as seen in Figure 6a, are almost flat across the entire measured range, and the values at 1 THz for a thin and a thick polymer are~1.57 and~1.62, respectively, which are close to the values observed earlier for PET polymer [34,35]. The different n(ω) values for the thin and thick samples are caused by the different ratio between the hard and soft segments in the PET-DLA 4060 and PET-DLA 6040 copolymers.…”

Section: Dielectric Constantsupporting

confidence: 86%

Terahertz Time-Domain Spectroscopy of Graphene Nanoflakes Embedded in Polymer Matrix

et al. 2019

View full text Add to dashboard Cite

The terahertz time-domain spectroscopy (THz-TDS) technique has been used to obtain transmission THz-radiation spectra of polymer nanocomposites containing a controlled amount of exfoliated graphene. Graphene nanocomposites (1 wt%) that were used in this work were based on poly(ethylene terephthalate-ethylene dilinoleate) (PET-DLA) matrix and were prepared via a kilo-scale (suitable for research and development, and prototyping) in-situ polymerization. This was followed by compression molding into 0.3-mm-thick and 0.9-mm-thick foils. Transmission electron microscopy (TEM) and Raman studies were used to confirm that the graphene nanoflakes dispersed in a polymer matrix consisted of a few-layer graphene. The THz-radiation transients were generated and detected using a low-temperature–grown GaAs photoconductive emitter and detector, both excited by 100-fs-wide, 800-nm-wavelength optical pulses, generated at a 76-MHz repetition rate by a Ti:Sapphire laser. Time-domain signals transmitted through the nitrogen, neat polymer reference, and 1-wt% graphene-polymer nanocomposite samples were recorded and subsequently converted into the spectral domain by means of a fast Fourier transformation. The spectral range of our spectrometer was up to 4 THz, and measurements were taken at room temperature in a dry nitrogen environment. We collected a family of spectra and, based on Fresnel equations, performed a numerical analysis, that allowed us to extract the THz-frequency-range refractive index and absorption coefficient and their dependences on the sample composition and graphene content. Using the Clausius-Mossotti relation, we also managed to estimate the graphene effective dielectric constant to be equal to ~7 ± 2. Finally, we extracted from our experimental data complex conductivity spectra of graphene nanocomposites and successfully fitted them to the Drude-Smith model, demonstrating that our graphene nanoflakes were isolated in their polymer matrix and exhibited highly localized electron backscattering with a femtosecond relaxation time. Our results shed new light on how the incorporation of exfoliated graphene nanoflakes modifies polymer electrical properties in the THz-frequency range. Importantly, they demonstrate that the complex conductivity analysis is a very efficient, macroscopic and non-destructive (contrary to TEM) tool for the characterization of the dispersion of a graphene nanofiller within a copolyester matrix.

show abstract

Section: Dielectric Constantsupporting

confidence: 86%

Terahertz Time-Domain Spectroscopy of Graphene Nanoflakes Embedded in Polymer Matrix

et al. 2019

View full text Add to dashboard Cite

show abstract

“…2, and to compare it to the distance in frequency obtained for the setup with a sample. The measurements should be performed along all the bandwidth of the pho− tomixer to obtain a continuous spectrum of the refractive index [13,14,16]. The same result is possible to obtain much easier in a pulsed system.…”

Section: Discussionmentioning

confidence: 99%

Selected polymers on CW and pulsed THz investigations

Jarzab

Nowak

Walczakowski

et al. 2012

Opto-Electronics Review

View full text Add to dashboard Cite

show abstract

“…11 Additionally, metals are not ideal conductors in the terahertz range, 14 and dielectric materials that are amenable to fabrication at the appropriate scale, such as polymers, are often very lossy. [15][16][17] Thus, it can be challenging to produce efficient terahertz devices. In this way, absorption can prevent the terahertz-range adoption of techniques that are popular at lower frequencies.…”

Section: Introductionmentioning

confidence: 99%

Tutorial: Terahertz beamforming, from concepts to realizations

et al. 2018

View full text Add to dashboard Cite

The terahertz range possesses significant untapped potential for applications including high-volume wireless communications, noninvasive medical imaging, sensing, and safe security screening. However, due to the unique characteristics and constraints of terahertz waves, the vast majority of these applications are entirely dependent upon the availability of beam control techniques. Thus, the development of advanced terahertz-range beam control techniques yields a range of useful and unparalleled applications. This article provides an overview and tutorial on terahertz beam control. The underlying principles of wavefront engineering include array antenna theory and diffraction optics, which are drawn from the neighboring microwave and optical regimes, respectively. As both principles are applicable across the electromagnetic spectrum, they are reconciled in this overview. This provides a useful foundation for investigations into beam control in the terahertz range, which lies between microwaves and infrared light. Thereafter, noteworthy experimental demonstrations of beam control in the terahertz range are discussed, and these include geometric optics, phased array devices, leaky-wave antennas, reflectarrays, and transmitarrays. These techniques are compared and contrasted for their suitability in applications of terahertz waves.

show abstract

Studying of dielectric properties of polymers in the terahertz frequency range

Cited by 60 publications

References 19 publications

Terahertz Time-Domain Spectroscopy of Graphene Nanoflakes Embedded in Polymer Matrix

Terahertz Time-Domain Spectroscopy of Graphene Nanoflakes Embedded in Polymer Matrix

Selected polymers on CW and pulsed THz investigations

Tutorial: Terahertz beamforming, from concepts to realizations

Contact Info

Product

Resources

About