Theoretical modeling and design of photonic structures in zeolite nanocomposites for gas sensing. Part II: volume gratings.

The suitability of holographic structures fabricated in zeolite nanoparticle-polymer composite materials for gas sensing applications has been investigated. Theoretical modeling of the sensor response (i.e., change in hologram readout due to a change in refractive index modulation or thickness as a result of gas adsorption) of different sensor designs was carried out using the Raman-Nath theory and Kogelnik's coupled wave theory. The influence of a range of parameters on the sensitivity of holographically recorded surface and volume photonic structures has been studied, namely, hologram geometry, hologram thickness and spatial frequency, reconstruction wavelength, and zeolite nanoparticle refractive index. From this, the optimum fabrication conditions for both surface and volume holographic gas sensor designs have been identified. Here in Part II, results from modeling of the influence of design on the sensor response of holographically recorded volume grating structures for gas sensing applications are reported.