2 research outputs found
Visualizing Optical Phase Anisotropy in Black Phosphorus
Layered
black phosphorus has triggered enormous interest since
its recent emergence. Compared to most other two-dimensional materials,
black phosphorus features a moderate band gap and pronounced in-plane
anisotropy, which stems from the unique atomic-puckering crystal structure.
The future potential of black phosphorus in optoelectronics demands
a deeper understanding of its unique anisotropic behavior. In particular,
the phase information on light when interacting with the material
is imperative for many applications in the optical regime. In this
work we have comprehensively studied a wide range of optical anisotropic
properties of black phosphorus, including the Raman scattering, extinction
spectra, and phase retardance by utilizing conventional spectral measurements
and a uniquely developed interferometric spectroscopy and imaging
technique. The phase retardance of light passed through black phosphorus
is exploited in conjunction with polarization interferometric techniques
to demonstrate an optical contrast an order of magnitude higher than
a purely polarization-based measurement could offer
Giant Chiral Optical Response from a Twisted-Arc Metamaterial
We demonstrate enormously strong
chiral effects from a photonic
metamaterial consisting of an array of dual-layer twisted-arcs with
a total thickness of ∼λ/6. Experimental results reveal
a circular dichroism of ∼0.35 in the absolute value and a maximum
polarization rotation of ∼305°/λ in a near-infrared
wavelength region. A transmission of greater than 50% is achieved
at the frequency where the polarization rotation peaks. Retrieved
parameters from measured quantities further indicate an actual optical
activity of 76° per λ and a difference of 0.42 in the indices
of refraction for the two circularly polarized waves of opposite handedness