Diatoms can be regarded as self-reproducing photonic crystal slab waveguides due to their silica cell walls that exhibit periodic pore patterns. The algae thus offer possibilities for biotechnological production of photonic crystals. Two techniques for incorporating organic laser dyes into the structures are demonstrated. First, Rhodamine B was covalently attached to the silica by an aminoalkylsilane linker. Second, highly fluorescent Rhodamine derivatives added to the culture medium were successfully taken up by the diatoms and deposited into the shell. By this techniques, it is possible to cultivate dye functionalized diatoms with emission behaviour adapted to photonic resonances.
The formation of holographic gratings in an azo-glass is investigated for the simple case of an intensity grating in the s-polarization of the recording beams. A dual grating is formed as a function of time with a refractive index grating and a relief grating. The diffraction efficiency as a function of recording time is discussed in a model of 2 consecutive processes with a phase shift. A material transport process is involved in the formation of relief patterns. A thermal erasure process at the glass transition is compared with an optical process.