Single-defect photonic crystal cavity laser fabricated by a combination of laser holography and focused ion beam lithography

Large-scale, high-throughput fabrication of photonic crystal (PC)-based devices was achieved by using a combination of laser holography (for background PC generation) and focused ion beam lithography (for defect formation). An array of InP-based square-lattice PC lasers with a single air-hole defect was fabricated by this combined lithography. The resultant lasers consistently exhibited two lasing modes, which were identified as quadrupole and dipole modes on the basis of their spectral and polarization properties. The high cavity Q-factor (similar to 2200) and low laser threshold (similar to 0.25 mW) indicated that the laser quality was comparable to that of the PC lasers formed by electron-beam lithography.