Prakash Pitchappa

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We experimentally demonstrate a micromachined reconfigurable metamaterial with polarization independent characteristics for multiple resonances in terahertz spectral region. The metamaterial unit cell consists of eight out-of-plane deformable microcantilevers placed at each corner of an octagon ring. The octagon shaped unit cell geometry provides the(More)
We experimentally demonstrate the active manipulation of terahertz (THz) waves using a periodic array of electrostatically actuated subwavelength microelectromechanical system cantilevers, which effectively behave like a metamaterial. The design methodology for achieving desired ONand OFF-state resonance frequencies through electromechanical optimization is(More)
We demonstrate the design, fabrication, and characterization of a polycrystalline-silicon-based photonic crystal Fabry-Perot etalon, which is aimed to work in the mid-infrared wavelengths. The highly reflective mirrors required in a Fabry-Perot etalon are realized by freestanding polycrystalline-silicon-based photonic crystal membranes with etched circular(More)
We present the design, simulation, and characterization of structurally reconfigurable metamaterials showing terahertz (THz) frequency switching with polarization-insensitive response. The metamaterial unit cell consists of an octagon ring with eight out-of-plane deformable cantilevers placed at each of its vertex. The polarization insensitive(More)
We report the first thermal study of a triple band plasmonic nanoantenna strongly coupled to a molecular mode at mid IR wavelength (MW IR). The hybrid plasmonic structure supports three spatially and spectrally variant resonances of which two are magnetic and one is dipolar in nature. A hybridized mode is excited by coupling the structure's plasmonic mode(More)
We experimentally demonstrated a free-standing two-dimensional (2-D) photonic crystal (PhC) aluminum nitride (AlN) membrane to function as a free space (or out-of-plane) reflector working in the mid infrared region. By etching circular holes of radius 620nm in a 330nm thick AlN slab, greater than 90% reflection was measured from 3.08μm to 3.78μm, with the(More)
We report an array of prestressed MEMS cantilever as active metamaterial for dynamic manipulation of terahertz waves. The electrostatically actuated microcantilevers integrated into split ring resonator and electrical split ring resonator unit cell, further enables active tuning of magnetic and electrical resonance, respectively. The actuation method of(More)
Controlling the phase of local radiation by using exotic metasurfaces has enabled promising applications in a diversified set of electromagnetic wave manipulation such as anomalous wavefront deflection, flat lenses, and holograms. Here, we theoretically and experimentally demonstrate an active phase transition in a micro-electromechanical system-based(More)
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