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Updated: Jun 16, 2026

Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
Published on: November 30, 2012
Square lattice photonic crystal point-shifted nanocavity with lowest-order whispering-gallery mode
Tsan-Wen Lu1, Pin-Tso Lin, Kuan-Un Sio
1Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Rm. 415 CPT Building, 1001 Ta Hsueh Road, Hsinchu 300, Taiwan. ricky.eo94g@nctu.edu.tw
Abstract:
We propose a point-shifted nanocavity based on square lattice photonic crystal, which sustains a lowest-order whispering-gallery (WG) mode. In simulation, the optimized WG mode (quality (Q) factor approximately 14,000) in point-shifted nanocavity can be with smaller mode volume (approximately 5.5(lambda/2n)(3)) but larger nano-post tolerance than those in single-defect cavity design. From well-fabricated device, single WG mode lasing with measured Q factor of 4,100 and low threshold of 160 microW is obtained. Besides, we also observe the changed polarization of WG mode due to modal symmetry breaking caused by the presence of a nearby dielectric nano-particle, which would be useful in sensing molecule binding or attaching for bio-chemical applications.
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