We present simple physical and chemical procedures that allow tuning and modification of the topography of gratings present in optical storage discs into geometries optimal for grating coupled plasmon resonance excitation. After proper metal coating, the tuned surfaces exhibit sharp plasmon resonances that can be excited at wavelengths ranging from 260 nm to over 2.7 μm with relatively high quality factors. As an immediate exemplary application, use of such optimized gratings in aqueous medium for refractive index measurement is demonstrated.

Abstract. We have developed a portable, breast margin assessment probe leveraging diffuse optical spectroscopy to quantify the morphological landscape of breast tumor margins during breast conserving surgery. The approach presented here leverages a custom-made 16-channel annular photodiode imaging array (arranged in a 4 × 4 grid), a raster-scanning imaging platform with precision pressure control, and compressive sensing with an optimized set of eight wavelengths in the visible spectral range. A scalable Monte-Carlo-based inverse model is used to generate optical property [μ 0 s ðλÞ and μ a ðλÞ] measures for each of the 16 simultaneously captured diffuse reflectance spectra. Subpixel sampling (0.75 mm) is achieved through incremental x , y raster scanning of the imaging probe, providing detailed optical parameter maps of breast margins over a 2 × 2 cm 2 area in ∼9 min. The morphological landscape of a tumor margin is characterized using optical surrogates for the fat to fibroglandular content ratio, which has demonstrated diagnostic utility in delineating tissue subtypes in the breast.

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Indium tin oxide is used as a top cladding electrode of optical disk resonators with subwavelength size in all dimensions. Calculated quality (Q)-factors exceed 10⁴ in visible wavelengths (650-670nm). The disk aspect ratio is an important parameter to optimize the resonator properties. The Q-factor and threshold material gain based on finite-difference time-domain method are optimized for eight different disk resonator optical modes. Proposed cavity designs are promising for building electrically-pumped, low-threshold nano-lasers at room temperature.