Omnidirectional color filters capitalizing on a nano-resonator of Ag-TiO2 -Ag integrated with a phase compensating dielectric overlay

Chul Soon Park, Vivek Raj Shrestha, Sang Shin Lee*, Eun Soo Kim, Duk Yong Choi

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    94 Citations (Scopus)

    Abstract

    We present a highly efficient omnidirectional color filter that takes advantage of an Ag-TiO2 -Ag nano-resonator integrated with a phase-compensating TiO 2 overlay. The dielectric overlay substantially improves the angular sensitivity by appropriately compensating for the phase pertaining to the structure and suppresses unwanted optical reflection so as to elevate the transmission efficiency. The filter is thoroughly designed, and it is analyzed in terms of its reflection, optical admittance, and phase shift, thereby highlighting the origin of the omnidirectional resonance leading to angle-invariant characteristics. The polarization dependence of the filter is explored, specifically with respect to the incident angle, by performing experiments as well as by providing the relevant theoretical explanation. We could succeed in demonstrating the omnidirectional resonance for the incident angles ranging to up to 70°, over which the center wavelength is shifted by below 3.5% and the peak transmission efficiency is slightly degraded from 69%. The proposed filters incorporate a simple multi-layered structure and are expected to be utilized as tri-color pixels for applications that include image sensors and display devices. These devices are expected to allow good scalability, not requiring complex lithographic processes.

    Original languageEnglish
    Article number8467
    JournalScientific Reports
    Volume5
    DOIs
    Publication statusPublished - 2015

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