Fig. 6: Polarisation-resolved SHG in a TMDC metasurface.
From: Tunable unidirectional nonlinear emission from transition-metal-dichalcogenide metasurfaces
a Schematic of the crystal orientation of the MoS2 with respect to the metasurface lattice (shown by primitive vectors \({\hat{\ell }}_{1}\) and \({\hat{\ell }}_{2}\)) and incident polarisation (\(\hat{{{{{{\boldsymbol{p}}}}}}}\): polarisation unit vector). The lab frame axis and armchair direction unit vectors are shown by \(\hat{{{{{{\boldsymbol{x}}}}}}}\), \(\hat{{{{{{\boldsymbol{y}}}}}}}\) and \(\hat{{{{{{\boldsymbol{a}}}}}}}\), respectively. b Simulated polarisation resolved SHG, in the forward direction, as a function of angle between pump polarisation and lab frame \({\phi }_{p}\) and pump wavelength when angle between armchair direction and lab frame \({\phi }_{a}=0\). The vertical dashed lines represent the spectral positions of the magnetic quadrupole (MQ), electric dipole (ED), the point in close vicinity of electric dipole (ED*), and magnetic dipole (MD). c Polarisation resolved SHG as a function of \({\phi }_{p}\) (when \({\phi }_{a}=0\)), at the wavelengths marked MQ, ED, ED* and MD. d Measured polarisation resolved SHG as a function of \({\phi }_{p}\) (when \({\phi }_{a}=30^\circ\)) of metasurface C at ED. e Simulated polarisation resolved SHG as function of \({\phi }_{p}\) (when \({\phi }_{a}=30^\circ\)) of metasurface C at ED.
