refractive index $n=3.5$, with an air gap $L$. To improve the quality factors of the modes, as well as to improve collection efficiency through modification of the far-field profiles, optimization of the lattice structure was performed by varying the outward shift ($s$) and smaller radius ($r_{sm}$) of the six holes nearest to the cavity and by varying the air gap separation ($L$) between the membrane and the bottom reflector. While these optimization techniques have been employed by other groups to study different PhC cavity structures[@kim2006; @beveratos2009; @haddadi2012], we combine the optimization of several parameters and demonstrate the optimization experimentally in our fabricated H1 devices. Here we will primarily discuss the role of the bottom reflector and the effect of tuning $s/a$ for the H dipole mode. A discussion of the influence of tuning $r_{sm}/r$ can be found in Appendix \[fdtd\]. Simulation and experimental results for the orthogonally polarized V dipole mode can be found in Appendix \[Vmode\].

![(a) Simulated Q of the H dipole mode as a function of $s/a$. Simulations without a bottom reflector are represented by the blue circles (labeled ‘no R’), and simulations with a bottom reflector separated by an air gap of $L=925$ nm are represented 