Single order resonances of square micro-pillar cavities by prism coupling

Single order resonances of large-sized square micro-pillar cavities have been measured by using prism coupling with over 60% coupling efficiency. We have qualitatively compared the observed single order resonances with 2-D finite-difference time-domain (FDTD) simulation of a micron-sized square micro-cavity coupled with a planewave illuminated dielectric flat interface in close proximity. A coupling efficiency of over 70% can be attained in a selected range of incident angles near the critical angle of total internal reflection. The FDTD square micro-cavity resonance field distribution reveals a periodic array of field extrema, which can be attributed to K-space modes.