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Photonic crystal surface-emitting lasers enabled by an accidental Dirac point

United States Patent

December 2, 2014
View the Complete Patent at the US Patent & Trademark Office
A photonic-crystal surface-emitting laser (PCSEL) includes a gain medium electromagnetically coupled to a photonic crystal whose energy band structure exhibits a Dirac cone of linear dispersion at the center of the photonic crystal's Brillouin zone. This Dirac cone's vertex is called a Dirac point; because it is at the Brillouin zone center, it is called an accidental Dirac point. Tuning the photonic crystal's band structure (e.g., by changing the photonic crystal's dimensions or refractive index) to exhibit an accidental Dirac point increases the photonic crystal's mode spacing by orders of magnitudes and reduces or eliminates the photonic crystal's distributed in-plane feedback. Thus, the photonic crystal can act as a resonator that supports single-mode output from the PCSEL over a larger area than is possible with conventional PCSELs, which have quadratic band edge dispersion. Because output power generally scales with output area, this increase in output area results in higher possible output powers.
Chua; Song Liang (Singapore, SG), Lu; Ling (Cambridge, MA), Soljacic; Marin (Belmont, MA)
Massachusetts Institute of Technology (Cambridge, MA)
13/ 771,935
February 20, 2013
GOVERNMENT SUPPORT This invention was made with Government support under Grant No. W911NF-07-D-0004 awarded by the Army Research Office, under Grant No. DMR-0819762 awarded by the National Science Foundation, and under Grant Nos. DE-SC0001299 and DE-FG02-09ER46577 awarded by the Department of Energy. The Government has certain rights in this invention.