Large-Area Low-Cost Plasmonic Perfect Absorber Chemical Sensor Fabricated by Laser Interference Lithography

Abstract

We employ laser interference lithography as a reliable and low-cost fabrication method to create nanowire and nanosquare arrays in photopolymers for manufacturing plasmonic perfect absorber sensors over homogeneous areas as large as 5.7 cm 2 . Subsequently, we transfer the fabricated patterns into a palladium layer by using argon ion beam etching. Geometry and periodicity of our large-area metallic nanostructures are precisely controlled by adjusting the interference conditions during single-and double-exposure processes, resulting in active nanostructures over large areas with spectrally selective perfect absorption of light from the visible to the near-infrared wavelength range. In addition, we demonstrate the method's applicability for hydrogen detection schemes by measuring the hydrogen sensing performance of our polarization independent palladium-based perfect absorbers. Since palladium changes its optical and structural properties reversibly upon hydrogenation, exposure of the sample to hydrogen causes distinct and reversible changes within seconds in the absorption of light, which are easily measured by standard microscopic tools. The fabricated large-area perfect absorber sensors provide nearly perfect absorption of light at 730 and 950 nm, respectively, and absolute reflectance changes from below 1% to above 4% in the presence of hydrogen. This translates to a relative signal change of almost 400%. The large-area and fast manufacturing process makes our approach highly attractive for simple and low-cost sensor fabrication, and therefore, suitable for industrial production of plasmonic devices in the near future.

Defining the plasmonic cavity performance based on mode transitions to realize highly efficient device design

“…[15][16][17][18][19][20][21] Factors like flexibility and simplicity in fabrication, good geometrical tolerance, large dielectric layer thicknesses with superior device characteristics, and low-cost processing are essential for developing next-generation devices with multiple applications. [22][23][24][25][26][27][28][29] Significantly, the nanoparticle shape, material, design, and size in a plasmonic device play considerable roles in determining the localized surface plasmon resonance (LSPR) and near-field enhancement properties. [30][31][32][33][34][35][36] In addition to these parameters, it is necessary to consider the geometrical edge effect, which influences the near field enhancement in plasmonic nanostructures.…”

Recent Progress in Active Optical Metasurfaces

“…As summarized in a recent review paper, beyond the noble metals such as silver and gold that have been widely used in nanooptics, alternative materials that can support plasmonic resonance have been recently studied. Among these materials, magnesium (Mg) and palladium (Pd) have been intensively investigated due to their tremendously attractive material characteristics that can be exploited to enabling reconfigurable metasurfaces.…”

“…Despite the superior plasmonic properties (lower optical loss, etc.) of Mg in the visible region, Pd (and Pd alloy) based metasurfaces have been shown to be promising for hydrogen detection of faster dynamics in the low pressure regime . Moreover, the intrinsic hysteresis behavior observed in Pd's plasmonic response offers more information about its reconfigurability, which can potentially be used for a plasmonic memory effect.…”

Parallel Laser Micro/Nano‐Processing for Functional Device Fabrication

“…After photo‐exposure and development, the structures on photoresist can be transferred to substrates by etching or lift‐off process. The etching methods include a series of semiconductor manufacturing methods, such as RIE, ion beam etching (IBE), which can provide great fabrication quality. The structures can also be modified by annealing.…”