In-plane hyperbolic polariton tuners in terahertz and long-wave infrared regimes

Abstract

One of the main bottlenecks in the development of terahertz (THz) and long-wave infrared (LWIR) technologies is the limited intrinsic response of traditional materials. Hyperbolic phonon polaritons (HPhPs) of van der Waals semiconductors couple strongly with THz and LWIR radiation. However, the mismatch of photon − polariton momentum makes far-field excitation of HPhPs challenging. Here, we propose an In-Plane Hyperbolic Polariton Tuner that is based on patterning van der Waals semiconductors, here α-MoO3, into ribbon arrays. We demonstrate that such tuners respond directly to far-field excitation and give rise to LWIR and THz resonances with high quality factors up to 300, which are strongly dependent on in-plane hyperbolic polariton of the patterned α-MoO3. We further show that with this tuner, intensity regulation of reflected and transmitted electromagnetic waves, as well as their wavelength and polarization selection can be achieved. Our results can help the development of THz and LWIR miniaturized devices.

Bicolor Regulation of an Ultrathin Absorber in the Mid-Wave Infrared and Long-Wave Infrared Regimes

“…Mid-wave infrared (MWIR, 3–5 μm) and long-wave infrared (LWIR, 8–14 μm) regions are key components of the mid-infrared (MIR) transparent atmospheric window. − Thermal radiation regulators focus on the modulation of MWIR and LWIR regions and can be applied in numerous branches of science and technology, including optics, thermodynamics, materials science, infrared (IR) encryption, thermal camouflage, , and smart windows . In the past decades, optical coatings of absorbing dielectrics and finite metals have been extensively studied to realize ultrathin absorbers with desirable optical absorption properties. , The method of breaking physical geometric symmetry has been systematically investigated in thermal photonics and applied in some IR-based areas, such as radiative cooling, , energy harvesting, , and thermal beams .…”

Near-Field Terahertz Morphological Reconstruction Nanoscopy for Subsurface Imaging of Protein Layers

“…Terahertz (THz) waves typically refer to the electromagnetic radiation spanning a frequency range of 0.1–10 THz. − Due to their broadband, nondestructive, label-free, and biosensitive features, − THz techniques have found increasing imaging applications in diverse fields including biomedicine and materials science. − However, the spatial resolution of conventional far-field-based THz techniques is restricted by the wavelength, unable to exceed the Rayleigh diffraction limit . Recently, the development of THz scattering-type scanning near-field optical microscopy (THz s-SNOM) breaks the Rayleigh diffraction limit and enables a nanometer spatial resolution. − A THz s-SNOM system integrates a THz spectroscopy system with a tapping-mode AFM and has been applied to nanoscopic imaging of various functional structures such as InAs nanowire, graphene layers, Bi 2 Se 3 layers, and gold structures .…”

Coupling into Hyperbolic Carbon-Nanotube Films with a Deep-Etched Antenna Grating

“…To overcome such a limitation, solutions have been proposed based on nanopatterning intrinsically anisotropic materials in order to achieve the photon-polariton momentum match. For instance, recent studies have reported promising enhanced performances of nanopatterned hBN and MoO 3 , in the mid-IR and THz spectral region. One alternative approach relies on carbon-nanotube (CNT) films.…”