Sensing self-assembled alkanethiols by differential transmission interrogation with terahertz metamaterials

Abstract

Surface-enhanced electromagnetic response in the resonant regions of split-ring resonators offers a sensitive way to probe the surface dipoles formed by alkanethiol molecules with a terahertz wave by a differential transmission (DT) interrogation method. The DT signal mainly comes from the interaction between alkanethiols and metamaterials by electron transfer and/or the variation of the dielectric constant. The Lorentz model is used to demonstrate the principle of DT interrogation theoretically, which suggests the variation of both frequency and damping of resonance can be captured cooperatively. This method has been employed to experimentally demonstrate the sensing feasibility for the chain length dependence of the alkanethiol molecules. Numerical simulations confirm that the enhancement is large at the gap and corner regions of this kind of metamaterials.

Self-referenced sensing based on terahertz metamaterial for aqueous solutions

“…Hence, metamaterial-based sensors, operated in THz range, has been employed in probing the specific interactions between biomolecules 16 and selfassembled molecular monolayers on the metastructure. 17 Remarkably, however, there are very few reports on water solutions sensing based on THz metamaterials, let alone the determination of molecular or ionic concentrations. 3 In this work, we reported an aqueous solution sensing method by using THz metamaterials.…”

“…This resonant mode is equivalent to a LC resonance due to the circular currents induced by the THz wave in the metamaterial. 18 As done in our previous work, 17 we define difference value between the maximum and minimum values as DPV ¼ A peak À A valley , where A peak is the peak amplitude and A valley is the valley amplitude (minimum value in case of valley absent as shown in Fig. 3(a)).…”

Solid analyte and aqueous solutions sensing based on a flexible terahertz dual-band metamaterial absorber

“…[10][11][12][13] Recently, THz metamaterial sensors have been used in the nondestructive and label-free detection of materials. [14][15][16][17][18] However, the sensitivity of the previously reported metamaterial biosensors is relatively lower due to the radiative and nonradiative loss. Most detection techniques were carried by different shifts in resonance frequency and rarely considered the changes in amplitude resonance.…”

Metamaterial-enhanced vibrational absorption spectroscopy for the detection of protein molecules

“…A common method using a metamaterial (MM) is dielectric surface plasmon resonance sensing in the THz region, where the presence of molecules can be detected by the spectral shift caused by absorption of the molecules on the device151617181920. Sensing with a split-ring resonator (SRR) is a typical example910131516172122. This structure is composed of a tiny gap area, whose resonant frequency can be well described by an equivalent LC circuit.…”