Tm optical switch based on slab photonic crystals with high degree of polarization and large extinction ratio

A TMOS based on slab PhCs with a high degree of DOP and a large EXR, wherein said TMOS based on slab PhCs with a high DOP and a large EXR, comprising:

• an upper slab PhC and a lower slab PhC connected as a whole;
• said upper slab PhC is a first square-lattice slab PhC with a TE bandgap, the cell of said first slab square-lattice slab PhCs includes a high-refractive-index rotating-square pillar, a single first flat dielectric pillar and a background dielectric, said first flat dielectric pillar is arranged horizontally, said first flat dielectric pillar enables an overall upper slab PhC to form as a whole, and said first flat dielectric pillar includes a high-refractive-index dielectric pipe and a low-refractive-index dielectric in the pipe, or a high-refractive-index flat film, or a low-refractive-index dielectric;
• said lower slab PhC is a second square-lattice slab PhC with a complete bandgap, the unit cell of said second square-lattice slab PhC includes a high-refractive-index rotating-square pillar, a single second flat dielectric pillar and a background dielectric, said second flat dielectric pillar is arranged horizontally, said second flat dielectric pillar enables an overall lower slab PhC to form as a whole, and said second flat dielectric pillar is a high-refractive-index dielectric pillar;
• said background dielectric is a low-refractive-index dielectric;
• and a normalized operating frequency of said TMOS with a high DOP and a large EXR is 0.252 to 0.267.