Development of a Large-Area Plasmonic Sensor Substrate with Dielectric Subwavelength Gratings Using Nanoimprint Lithography

Abstract

We demonstrated an enhanced surface plasmon resonance (SPR) detection by incorporating subwavelength SiO2 gratings built on a thin silver film. Large-area SiO2 gratings were fabricated by nanoimprint lithographic technique and dry etching processes and used to sense a surface-limited biomolecular interaction. Numerical results based on rigorous coupled-wave analysis method exhibited that the dielectric gratings can provide a notable sensitivity improvement by 2 times, which is attributed to an increase in surface reaction area. As another possible application of the fabricated plasmonic substrate, experimental data of imaging the cell morphology were also presented. This study was intended to show the feasibility and extend the applicability of a large-area grating-based SPR substrate to diverse optical bioengineering fields.

Sensitive biological detection based on Langmuir–Blodgett films prepared fromdiluted silica suspensions

“…Besides ethylene glycol surfactant used on DIY water during the LB coating process, the only ETPTA monomer might be applied to get highly ordered arrays and templates. They can be fabricated as molds for soft lithography [23][24][25] and nanoimprint lithography [26,27] to produce highly uniform nanodots and nanohole arrays.…”

“…The obtained spectra are evidence of different Bragg diffractions with Fabry-Perot parallel beam lines showing high quality photonic crystal properties combined with the LB coating technique. The comparison was not shown between deposited and bare glass in the figures because no shifts or signals at specific wavelengths for various glass surfaces (not coated) were observed in the range of visible light [26,27]. Specific signals in wavelengths and linear shifts in wavelengths corresponding to partial pressure are important indicators in the selection of nanoporous film as a sensor surface for vapor detection.…”

Evanescent-field-coupled guided-mode sensor based on a waveguide grating

“…Among the wellknown couplers for mode excitation, a prism coupler and a grating coupler are used widely [9]. Dielectric diffraction gratings on a thin metal film, which are not thick enough to support guided modes (GMs), were also used in sensing structures to enhance the outcoupling efficiency to radiative diffraction orders of SPPs excited by a prism coupler [10][11][12][13][14][15][16]. For SPPs excited by white light, the gratings were implemented for the angular separation of the SPPs at different wavelengths [17].…”

Multi-color fluorescence imaging based on plasmonic wavelength selection and double illumination by white light

“…For transverse magnetic (TM)-polarized light, if an incidence beam satisfies the condition of surface plasmon resonance (SPR), the electromagnetic field is strongly enhanced and confined in the vicinity of the metal surface as a non-radiative evanescent field. When white light is incident to a gold substrate with a dielectric grating, the propagating surface plasmons are transmitted into the air via diffraction by a large-area grating pattern fabricated by nanoimprint lithography [6]. As the transmitted beam of a certain wavelength can be selected by changing an illumination angle of the white light, plasmonic wavelength splitter is feasible for transmission-type fluorescence imaging to overcome the limitations of conventional fluorescence microscopy described above.…”