Fig. 1: Photo-induced optical anisotropy.
From: Manipulating hyperbolic transient plasmons in a layered semiconductor
a Schematic diagram of the experimental setup and the transient hyperbolic plasmons. b Band structure of bulk BP near Z point in Brillouin region. The red arrows indicate the pump-induced electronic transition. c Normalized nano-FTIR amplitude s3,BP/s3,Si (green) and phase ϕ3,BP – ϕ3,Si (brown) spectra of the pump excited BP at τ = 200 fs with 0.5 mJ/cm2 pump fluence. The opened circles represent the experimental data, and the solid lines are from the dipole model calculation. d The real part of dielectric elements of the bulk BP. Dashed lines: pristine BP. Solid Lines: BP in non-equilibrium e, f IFCs of the BP at v/c = 950 cm−1, where v is the frequency of probe light and c is the velocity of light. e pristine BP. f BP in non-equilibrium. g Schematic of the hyperbolic plasmons launched by the edge of the gold disk. The red arrows represent energy rays. h The near-field image s3 of pristine and non-equilibrium BP/gold stacked structure at τ = 200 fs with 0.5 mJ/cm2 pump fluence. The frequency region of the probe is v/c = 850–1200 cm−1. The white dashed lines in g, h mark the dark edge of the gold disk.
