Wafer-Scale Photonic and Plasmonic Crystal Sensors

Matthew C. George Optics Department, Moxtek, Inc., Orem, USA Jui-Nung Liu Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, USA Arash Farhang Optics Department, Moxtek, Inc., Orem, USA Brent Williamson Optics Department, Moxtek, Inc., Orem, USA Mike Black Optics Department, Moxtek, Inc., Orem, USA Ted Wangensteen Optics Department, Moxtek, Inc., Orem, USA James Fraser Optics Department, Moxtek, Inc., Orem, USA Rumyana Petrova Optics Department, Moxtek, Inc., Orem, USA Brian T. Cunningham Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, USA

200 mm diameter wafer-scale fabrication, metrology, and optical modeling results will be reviewed for surface plasmon resonance (SPR) sensors based on 2D metallic nano-dome and nano-hole arrays (NHA) as well as 1D photonic crystal sensors based on leaky-waveguide mode resonance, with potential applications in label free sensing, surface enhanced Raman spectroscopy (SERS), and surface-enhanced fluorescence spectroscopy (SEFS). Potential markets include micro-arrays for medical diagnostics, forensic testing, environmental monitoring, and food safety.

Wafer-scale optical metrology results will be compared to FDTD modeling and presented along with application-based performance results, including label-free plasmonic and photonic crystal sensing of both surface binding kinetics and bulk refractive index changes. In addition, SERS and SEFS results from a line scan microscope system will be presented for several 1D photonic crystal and 2D metallic array structures. Figure 1 presents fabrication and optical metrology results for various 1D and 2D photonic crystal and SPR sensors. Narrow-band photonic crystal resonance sensors showed quality factors over 200, although wafer-uniformity needs further improvement. Gold-coated nano-dome arrays for SERS applications showed gaps with spacing in the 10-20 nm range. Normal incidence extraordinary optical transmission (EOT) results for a 550 nm pitch nano-hole array showed good bulk refractive index sensitivity, however an intensity-based design with 665 nm pitch was chosen for use as a compact, label-free sensor at both 650 and 632.8 nm wavelengths. The optimized NHA sensor gives an SPR shift of about 480 nm per refractive index unit when detecting a series of 0-40% glucose solutions.

Figure 1

Figure 1. (a)-(d) Results for narrow band 1D photonic crystal sensors composed of TiO2 layer on SiO2 grating. (a) SEM cross-section, (b) normal incidence Reflectance, and 200mm diameter wafer maps for 7.5° reflectance showing (c) peak height and (d) peak wavelength uniformity. Red color corresponds to larger Reflectance or longer λ. (e) Au-coated nano-dome array sample. (f) EOT at normal incidence for 550 nm pitch NHA under 0-40% aqueous glucose solutions.

mgeorge@moxtek.com









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