Photonic crystal surface emitting lasers based on epitaxial regrowth

摘要

Photonic crystal surface emitting lasers (PCSELs) [1], shown schematically in Fig 1(a), offer the ultimate in control in semiconductor lasers, demonstrating power scaling with area as lasing occurs at the band edge [2], high single-mode powers [3], large scale coherent emission [4], control of the beam shape and polarization with design of the photonic crystal geometry [5], and beam steering [3] Previous PCSELs utilised the high refractive index contrast between semiconductor and voids created in the structure by wafer fusion [1–4] or by epitaxial re-growth [6]. However, the presence of voids presents possible issues in device reliability, and reproducibility, and the low refractive index of the PCSEL layer results in difficulties in the design of the lateral waveguide.