Phys.org August 4, 2022 A conventional optical phased arrays (OPA) based on a waveguide grating array suffers from strong cross talk between adjacent waveguides when the pitch is a half-wavelength or less. Researchers in Denmark theoretically described and experimentally demonstrated a two-dimensional aliasing-free beam steering regime for an integrated OPA with the entire 180° field of view (FOV). They achieved this by using a half-wavelength-pitch waveguide array combined with a trapezoidal slab grating as a single emitter. The OPA had a low sidelobe level of <−19dB while the beam was steered from −40∘ to +40∘, breaking the trade-off between FOV […]
Tag Archives: Beam steering
Slow light to speed up LiDAR sensors development
Phys.org January 14, 2020 Currently existing optical beam steering devices uses mechanics that make them large, unstable, heavy, with limited overall speed and a high cost. Optical phased arrays for steering beams requires many optical antennas. Researchers in Japan used a special waveguide “photonic crystal,” aimed through a silicon-etched medium. Light is slowed down and emitted to the free space when forced to interact with the photonic crystal. They engaged a prism lens to then direct the beam in the desired direction. The resulting method and device are small-sized, free of moving mechanics, setting the stage for a solid-state LiDAR. […]
Tuning terahertz beams with nanoparticles
Phys.org September 6, 2018 A team of researchers in the US (UT San Antonio, Los Alamos National Laboratory) demonstrated that when an assembly of ferromagnetic core (cobalt ferrite) and a ferroelectric shell (barium titanate) is operated in external magnetic fields, it exhibits a controllable amplitude modulation when the magnetic field is applied antiparallel to the THz wave propagation direction; yet the same assembly displays an additional phase modulation when the magnetic field is applied along the propagation direction. Phase modulation is a result of stress-mediated piezoelectricity of the outer ferroelectric shell. The findings could enable tiny, high frequency transistors, create […]