Manipulating the optical beam width in topological pseudospin-dependent waveguides using all-dielectric photonic crystals

We propose a width-tunable topological pseudospindependent waveguide (TPDW) which can manipulate the optical beam width using a heterostructure of all-dielectric photonic crystals (PhCs). The heterostructure can be realized by introducing a PhC featuring double Dirac cones into the other two PhCs with different topological indices. The topological pseudospin-dependent waveguide states (TPDWSs) achieved from the TPDW exhibit unidirectional transport and immunity against defects. As a potential application of our work, using these characteristics of TPDWSs, we further design a topological pseudospin-dependent beam expander which can expand a narrow beam into a wider one at the communication wavelength of 1.55 mu m and is robust against three kinds of defects. The proposed TPDW with widely adjustable width can better dock with other devices to achieve stable and efficient transmission of light. Meanwhile, all-dielectric PhCs have negligible losses at optical wavelengths, which provides the prospect of broad application in photonic integrated devices. (C) 2022 Optica Publishing Group.

Automated summary

Researchers propose a width-tunable topological pseudospindependent waveguide using a heterostructure of all-dielectric photonic crystals, which allows for manipulation of the optical beam width. The waveguide exhibits unidirectional transport and immunity against defects, making it suitable for applications such as beam expanders in photonic integrated devices for stable and efficient light transmission.