Dear Anish,

The short answer would be that you'd need to have not only the proper lattice configuration and constant but the high index of contrast between low and high "n" in the appropriate lattice sites. One can't get this contrast with silica and air. That's why one would use opals as a template for a subsequent inversion procedure. For example, take a look at our article:

https://www.researchgate.net/publication/233809471_Large-scale_synthesis_of_a_siliconphotonic_crystal_with_a_completethree-dimensional_bandgapnear_1.5_micrometres?ev=prf_pub

Regards,

Serge

Article Large-Scale Synthesis of a Silicon Photonic Crystal with a C...

The opals are materials with special spice structure. They may not be any photonic crystal if the refractive index contrast is too small. The required contrast depends on the crystal symmetri we realize and usually must have the contrast ratio around 2:1. So, the task of inverse is to obtain new structure, for example silicon-air (n=3.6) pair

instead of silica-air (n=1.42) pair.

Three attributes of a photonic crystal contribute to having a strong band gap.

1. Lattice should have isolated dielectric "globs." This better supports band gaps for the TE polarization.

2. Lattice should have continuously connected dielectric veins. This better supports band gaps for TM polarization.

3. Lattice should have as high of symmetry as possible (FCC/diamond). This produces better alignment between the stop bands for waves propagating in different directions.

The inverse opal best satisfies all of these. Aperiodic lattices can have even stronger band gaps due to having higher symmetry.

See Lecture 14 here for more information and pictures. I discuss this exact topic.

http://emlab.utep.edu/ee5390em21.htm

Hope this helps!