Fig. 1

Dipole-launching of hyperbolic polaritons. a Schematic of z-oriented dipole-launching of hyperbolic shear polaritons in a monoclinic crystal with off-diagonal permittivity (\({\varepsilon }_{xx}=-3.73+0.55\mathrm{i }, {\varepsilon }_{yy}=2.34, {\varepsilon }_{zz}=-3.73+0.55\mathrm{i },{\varepsilon }_{xy}=-1+0.3\mathrm{i}\)). b Schematic of z-oriented dipole-launching of symmetric hyperbolic polaritons in an orthorhombic crystal with a diagonal permittivity (\({\varepsilon }_{xx}=-3.73+0.55\mathrm{i }, {\varepsilon }_{yy}=2.34, {\varepsilon }_{zz}=-3.73+0.55\mathrm{i}\)). c Schematic of in-plane oriented dipole-launching of symmetry-broken hyperbolic polaritons in the same orthorhombic crystal as in (b). d–f Simulated real part of the near-field distribution E_z above the surface of the monoclinic or orthorhombic crystal, respectively. Perpendicular black lines represent the direction of crystal axis. g–i Corresponding absolute value of the two-dimensional FFT, with perpendicular white lines denoted as O1 and O2, the direction of the two effective optic axes. In (a–c) a₁, a₂ and a₃ denote vectors of the unit cell