As a next generation of detection technology, terahertz technology is very promising. In this work, a highly efficient terahertz wave absorber based on 3D graphene foam (3DG) is first reported. Excellent terahertz absorption property at frequency ranging from 0.1 to 1.2 THz is obtained owing to faint surface reflection and enormous internal absorption. By precise control of the constant properties for 3DG, the reflection loss (RL) value of 19 dB is acquired and the qualified frequency bandwidth (with RL value over 10 dB) covers 95% of the entire measured bandwidth at normal incidence, which far surpasses most reported materials. More importantly, the terahertz absorption performance of 3DG enhances obviously with increasing the incidence while majority of materials become invalid at oblique incidence, instead. At the incidence of 45°, the maximum RL value increases 50% from 19 to 28.6 dB and the qualified frequency bandwidth covers 100% of the measured bandwidth. After considering all core indicators involving density, qualified bandwidth, and RL values, the specific average terahertz absorption (SATA) property is investigated. The SATA value of 3DG is over 3000 times higher than those of other materials in open literatures.

Ultra-Broadband Wide-Angle Terahertz Absorption Properties of 3D Graphene Foam

Significance: An increasing interest in the area of biological effects at exposure of tissues and cells to the terahertz (THz) radiation is driven by a rapid progress in THz biophotonics, observed during the past decades. Despite the attractiveness of THz technology for medical diagnosis and therapy, there is still quite limited knowledge about safe limits of THz exposure. Different modes of THz exposure of tissues and cells, including continuous-wave versus pulsed radiation, various powers, and number and duration of exposure cycles, ought to be systematically studied.
Aim: We provide an overview of recent research results in the area of biological effects at exposure of tissues and cells to THz waves.
Approach: We start with a brief overview of general features of the THz-wave–tissue interactions, as well as modern THz emitters, with an emphasis on those that are reliable for studying the biological effects of THz waves. Then, we consider three levels of biological system organization, at which the exposure effects are considered: (i) solutions of biological molecules; (ii) cultures of cells, individual cells, and cell structures; and (iii) entire organs or organisms; special attention is devoted to the cellular level. We distinguish thermal and nonthermal mechanisms of THz-wave–cell interactions and discuss a problem of adequate estimation of the THz biological effects’ specificity. The problem of experimental data reproducibility, caused by rareness of the THz experimental setups and an absence of unitary protocols, is also considered.
Results: The summarized data demonstrate the current stage of the research activity and knowledge about the THz exposure on living objects.
Conclusions: This review helps the biomedical optics community to summarize up-to-date knowledge in the area of cell exposure to THz radiation, and paves the ways for the development of THz safety standards and THz therapeutic applications.

https://www.spiedigitallibrary.org/journals/journal-of-biomedical-optics/volume-26/issue-9/090902/Cellular-effects-of-terahertz-waves/10.1117/1.JBO.26.9.090902.pdf

Cellular effects of terahertz waves.

Application of terahertz spectroscopy in biomolecule detection

The generalized energy-based fragmentation (GEBF) method is extended to allow calculations of nuclear magnetic resonance (NMR) chemical shifts of macromolecular and condensed-phase systems feasible at a low computational cost. In this approach, NMR shielding constants in a large system are evaluated as a linear combination of the corresponding quantities from a series of small “electrostatically embedded” subsystems. Comparison of NMR shielding constants from the GEBF-X method [where X is an electronic structure method, such as Hartree–Fock (HF), density functional theory (DFT), ...] with those from the conventional quantum chemistry method for two representative systems verifies that the GEBF approach can reproduce the results of the conventional quantum chemistry method very well. This procedure has further been applied to compute NMR shielding constants of a large foldamer and a supramolecular aggregate, and the 15N shielding constant for CH3CN in the CHCl3 solvent. For the former two systems, the pred...

Accurate Prediction of NMR Chemical Shifts in Macromolecular and Condensed-Phase Systems with the Generalized Energy-Based Fragmentation Method.

Intermolecular weak interactions of crystalline purine and uric acid investigated by terahertz spectroscopy and theoretical calculation

Terahertz spectra of DNA nucleobase crystals: A joint experimental and computational study

Broadband spectra of 20 L-amino acids were obtained at room temperature by terahertz time-domain and infrared spectroscopy. The intensity of terahertz absorption peaks varied with the concentration...

Fang Wang

Papers

Terahertz spectra of DNA nucleobase crystals: A joint experimental and computational study

Broadband terahertz spectroscopy of amino acids

THz spectra and corresponding vibrational modes of DNA base pair cocrystals and polynucleotides

Terahertz spectra and weak intermolecular interactions of nucleosides or nucleoside drugs.

THz vibrational spectroscopy for RNA basepair cocrystals and oligonucleotide sequences.