September 2022
Spotlight Summary by Quynh Dang and Ho Wai Howard Lee
Polarization discrimination and surface sensing with a near-IR nanostructured hybrid mirror
Efficient manipulation on the polarization of light is fundamental for most of the photonic applications, ranging from imaging to optical communication.
Metasurface-based mirrors, such as periodically patterned, sub-wavelength non-diffracting thin films, have shown promise on offering an unpreceded degree of control over the polarization states of reflected light. However, these mirrors are usually less reflective and challenging for routine fabrication. The work by Buchnev et al. demonstrates a viable solution to bypass the lack of high-quality and easy-to-fabricate non-diffracting mirrors operating in the near IR region. To achieve high reflectivity for one polarization and suppress it for the orthogonal polarization, they engineered a resonant metal-dielectric mirror by pairing a Bragg reflector with a wire-grid nanograting. The Bragg reflector is structured to ensure a reflectivity level exceeding 99%, then complimented by the wire-grid polarizer, which acts as a non-diffracting polarization discriminating element. This configuration allows light coupled to the Tamm resonance to leak through the nanograting and interfere with the primary reflected light. Using straightforward fabrication techniques, they successfully fabricated structures that operate at the TE Tamm plasmon resonance with polarization distinction that approaches a 10:1 ratio for demonstrated devices, and potentially reach 50:1 with parameter optimization. They also exploit the tunability of the operating wavelength by shifting the Tamm resonance condition. This technique can potentially extend to the control of radial and azimuthal polarizations and is an easy-to-implement solution for on-chip control of light, optical processing, and compact narrowband light source.
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Metasurface-based mirrors, such as periodically patterned, sub-wavelength non-diffracting thin films, have shown promise on offering an unpreceded degree of control over the polarization states of reflected light. However, these mirrors are usually less reflective and challenging for routine fabrication. The work by Buchnev et al. demonstrates a viable solution to bypass the lack of high-quality and easy-to-fabricate non-diffracting mirrors operating in the near IR region. To achieve high reflectivity for one polarization and suppress it for the orthogonal polarization, they engineered a resonant metal-dielectric mirror by pairing a Bragg reflector with a wire-grid nanograting. The Bragg reflector is structured to ensure a reflectivity level exceeding 99%, then complimented by the wire-grid polarizer, which acts as a non-diffracting polarization discriminating element. This configuration allows light coupled to the Tamm resonance to leak through the nanograting and interfere with the primary reflected light. Using straightforward fabrication techniques, they successfully fabricated structures that operate at the TE Tamm plasmon resonance with polarization distinction that approaches a 10:1 ratio for demonstrated devices, and potentially reach 50:1 with parameter optimization. They also exploit the tunability of the operating wavelength by shifting the Tamm resonance condition. This technique can potentially extend to the control of radial and azimuthal polarizations and is an easy-to-implement solution for on-chip control of light, optical processing, and compact narrowband light source.
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Article Information
Polarization discrimination and surface sensing with a near-IR nanostructured hybrid mirror
Oleksandr Buchnev, Alexandr Belosludtsev, and Vassili A. Fedotov
Opt. Lett. 47(16) 4036-4039 (2022) View: Abstract | HTML | PDF