Thermally Tunable Absorption‐Induced Transparency by a Quasi 3D Bow‐Tie Nanostructure for Nonplasmonic and Volumetric Refractive Index Sensing at Mid‐IR

Abstract

harvesting, telecom, and sensing industries. [1][2][3][4][5][6] Controlled transmission of light, which has been attractive for centuries since the invention of the camera obscura, is an important subtopic of plasmonics. Ebbesen et al. fi rst experimentally provided evidence of unusually high optical transmission with effi ciency exceeding unity (a phenomenon known as extraordinary optical transmission (EOT)) through holey metal fi lm in 1998 [ 7 ] and demonstrate the possibility of overcoming a fundamental constraint, i.e., extremely low transmittivity of subwavelength apertures. Plasmon mediated transmission of light through subwavelength channels has inspired a great interest for many engineering applications ever since. EOT refers to the greatly enhanced optical transmission in an otherwise opaque metal fi lm patterned with periodic structure and can be dominated by the diffraction and/ or spoof plasmons. Another well-known transmission phenomenon namely electromagnetically induced transparency (EIT), however, refers to the resonant process observed in three-level atomic confi gurations, in which two optical beams are coherently coupled to two energy level transitions. [ 8 ] Due to the destructive interference between the amplitudes associated with different excitation pathways, the transmission of an optical beam can be greatly enhanced in a narrow frequency band. A metamaterial analogue of the atomic system is the coherent coupling between two deliberately designed resonant pathways in a single unit cell, where one supports the excitation of the so-called "bright mode" while the other the "dark mode." [ 9 ] In fact, such EITlike effect can be termed as plasmon-induced transparency in optical regime. [ 10 ] However, the maximal transparency achievable by the artifi cial system with resemblance to the atomic system is determined by the ratio of the line widths of the two resonance processes which is inherently limited by the metallic loss of the metamolecules. In view of such limitation, a suitable alternative is to combine the advantages of both worlds in a hybrid system where the broadband oscillation of plasmonic molecule can strongly interact with the narrowband absorption line of the dielectric and opens up a narrow transmission window through a process called hybridization-induced A nonresonant transmission process namely absorption-induced transparency (AIT) is demonstrated in a quasi 3D bow-tie nanostructure at mid-IR spectrum for the fi rst time. The quasi 3D structure is formed by self-aligning two metasurfaces obtained by the Babinet's principle which are linked to each other through a patterned layer of PMMA. It is shown that the vibrational absorption of poly(methyl methacrylate) (PMMA) at 5.79 µm can strongly infl uence the propagation characteristics of the quasi 3D structure and generate the absorption-induced transmission peak. A detailed parametric study is conducted on the process and its nonplasmonic characteristics are confi rmed. Later, the usefulness of the quasi 3D nanochannels of the ...

Microfluidic metamaterial sensor: Selective trapping and remote sensing of microparticles

“…1,2 This has led to the demonstration of numerous interesting electromagnetic properties such as negative refractive index, 3,4 perfect absorption, 5,6 sub-wavelength focusing, 7 and many more. [8][9][10] Interestingly, the properties of the metamaterials are strongly dependent on the geometry of their unit cell, and thereby passively and actively varying the size and shape of the unit cell, a precise control of the metamaterial properties can be readily achieved. [11][12][13][14][15][16][17][18] Alternatively, metamaterials are also explored as a sensing platform due to their strong response to the changes in the surrounding medium and strong enhancement of the field strengths at specific portions of the resonator geometry.…”

Rapid sample preparation with Lyse-It® for Listeria monocytogenes and Vibrio cholerae

“…In previous studies it was both theoretically and experimentally shown that the equilateral “bow-tie” geometry of the Lyse-It ® slide focuses microwaves leading to a significant thermal gradient and cavitation between the apexes [ 12 , 15 – 19 ]. These thermal gradients (expansion of water) were shown to create enormous stress on cell walls, resulting in complete membrane collapse and release of the intact cellular materials.…”

Heterogeneous Wafer Bonding Technology and Thin-Film Transfer Technology-Enabling Platform for the Next Generation Applications beyond 5G

“…There are many fingerprints for gases, liquids, and biomolecules in the MIR wavelength [ 150 , 151 , 152 , 153 , 154 , 155 , 156 , 157 , 158 , 159 ]. Correspondingly, the working wavelengths of many sensors are designed in the range of MIR [ 160 , 161 , 162 , 163 , 164 , 165 , 166 , 167 , 168 , 169 , 170 ]. In addition to microelectronics, Si is also one of the most popular materials in photonics [ 171 , 172 ].…”