Browsing by Author "Farooq, Hira (TTU)"

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    A pedagogical approach to relativity effects in quantum mechanics
    (2022) Grave De Peralta, Luis (TTU); Webb, Katrina C. (TTU); Farooq, Hira (TTU)
    A simple but precise approach to relativistic quantum mechanics is presented. The approach is based on the use of a Schrödinger-like, little-known but well-studied quantum mechanics wave equation. Such formal similitude allows undergraduate students to quantitatively explore how the results corresponding to a typical non-relativistic quantum problem change when the particle is moving at relativistic speeds. No additional mathematical skills are required. We argue in favor of the academic use of this approach for including the implications of the special theory of relativity in introductory quantum mechanics courses.
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    Coupled surface plasmon–phonon polariton nanocavity arrays for enhanced mid-infrared absorption
    (2022) Kachiraju, Satya R. (TTU); Nekrashevich, Ivan; Ahmad, Imtiaz (TTU); Farooq, Hira (TTU); Chang, Long; Kim, Sangsik (TTU); Kim, Myoung-Hwan (TTU)
    Resonant optical cavities are essential components in mid-infrared applications. However, typical film-type cavities require multilayer stacks with a micron-thick spacer due to mid-infrared wavelengths, and their performance is limited by narrow frequency tunability and angular sensitivity. We propose and experimentally demonstrate the subwavelength-scale (≈λ0/150) resonant nanocavity arrays that enhance the absorption spectrum of the device in the mid-infrared (10–12 microns) via excitation of coupled surface plasmon–phonon polaritons. The proposed metal–insulator–polar dielectric (gold–silicon–silicon carbide) structure supports a guided mode of the coupled surface polaritons in the lateral direction while vertically confining the mid-infrared wave within the 80 nm thick dielectric spacer. In particular, the subwavelength-scale (≈λ0/10) gratings are imposed to form Fabry–Pérot cavity arrays displaying angle-insensitive and frequency-tunable absorption of up to 80% of the optical power in the mid-infrared. Our work should benefit diverse mid-infrared applications and novel designs of polariton-based photonic devices.