Performance of conformal guided mode resonance filters.
ABSTRACT Guided mode resonance (GMR) filters are highly functional micro-optics capable of narrowband spectral filtering. GMR devices have previously been demonstrated on flat substrates using a wide range of materials and configurations. In this Letter, we apply a soft lithographic technique followed by the deposition of dielectric layers to generate GMR filters on a concave lens surface. Resonances of the resulting conformal GMR filters are experimentally measured and characterized, and the results are compared to the performance of similar GMR filters fabricated on flat surfaces.
Conference Paper: Small-aperture guided-mode-resonance filter with cavity resonators[Show abstract] [Hide abstract]
ABSTRACT: A cavity-resonator-integrated guided-mode-resonance filter (CRIGF) consisting of a grating coupler (GC) and a pair of distributed-Bragg-reflectors (DBRs) on a thin film waveguide has been recently proposed and investigated to provide a narrow-band reflection spectrum for an incident wave of a small beam width from the free space. A CRIGF demonstrated so far shows polarization dependence because propagation constants of guided waves excited by GC are different between TE and TM incident waves. In order to construct a polarization-independent guided-mode resonance filter with small aperture, an integration of two CRIGFs crossed each other was proposed and discussed in this paper. A device was designed for a resonance wavelength of 1550 nm and its reflection and transmission spectra were predicted by a newly developed analysis based on the coupled-mode theory. A reflectance of 96 % with 1 nm bandwidth was expected for an incident beam diameter of 10 μm. A test sample working at 846 nm was fabricated and characterized. A Ge:SiO2 guiding core layer was deposited on a SiO2 glass substrate, and GC and DBRs were formed by the electron-beam direct writing lithography. Measured reflection spectra for TE and TM incident beams were well coincident with each other.Electronic Components and Technology Conference (ECTC), 2012 IEEE 62nd; 01/2012
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ABSTRACT: A guided-mode resonance filter integrated in a waveguide cavity resonator constructed by two distributed Bragg reflectors is designed and fabricated for miniaturization of aperture size. Reflection efficiency of >90% and wavelength selectivity of 0.4 nm are predicted in the designed SiO(2)-based filter with 50-μm aperture by a numerical calculation using the finite-difference time-domain method. A maximum reflectance of 67% with 0.5-nm bandwidth is experimentally demonstrated by the fabricated device at around 850-nm wavelength.Optics Express 01/2012; 20(2):1444-9. DOI:10.1364/OE.20.001444 · 3.53 Impact Factor
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ABSTRACT: Incorporating optical structures on curved lens surfaces can improve performance, consolidate functions, and create novel, miniaturized devices. Although commonly found in biological systems, patterning of micro- and nano-optical structures on curved surfaces is challenging for conventional methods. Previous works have demonstrated the ability to pattern curved surfaces but have done little to create functioning devices. In this Letter, we describe a novel spray-coating technique coupled with interferometric exposure and dry etching to create near-IR wire-grid polarizers on convex lens surfaces. Experimental measurements show extinction ratios of >40:1 and transmission values of >80%, which are comparable to modeled results of similar polarizers on flat surfaces.Optics Letters 03/2012; 37(6):1088-90. DOI:10.1364/OL.37.001088 · 3.18 Impact Factor