  The novel phototunable photonic structures based on electrochemically etched
silicon filled with four photochromic azobenzene-containing compounds,
bent-shaped low molar mass substance and side-chain polymethacrylates and
copolyacrylate, were prepared and their photooptical properties were studied.
It was found that irradiation of these composites with polarized blue light
results in spectral changes in photonic band gap (split of the cavity mode)
associated with cooperative photoorientation of azobenzene moieties inside
silicon pores in direction perpendicular to the polarization plane of the
incident light. Kinetics of the photoinduced split is studied. The observed
phototoinduced split is completely reversible and heating of the composites to
temperatures above isotropization or glass transitions fully recovers the
initial spectral shape of photonic band gap. Thermal and temporal stability of
the obtained photoinduced split were comparatively studied, and it was found
that for composites with bent-shaped substance and polymethacrylate shape of
the reflectance spectra does not change over time at room temperature. The
prepared composites have high potential for the different applications in
photonics.
