Photonic Crystal spatial filters, apart from stand-alone spatial filtering function, can also suppress multi-transverse-mode operation in laser resonators. Here it is shown that such photonic crystals can be designed by solving the inverse problem: for a given spatial filtering profile. Optimized Photonic Crystal filters were fabricated in photosensitive glass. Experiments have shown that such filters provide a more pronounced filtering effect for total and partial transmissivity conditions.
Gailevicius, D., Purlys, V., Peckus, M., Gadonas, R., Staliunas, K. Spatial Filters on Demand Based on Aperiodic Photonic Crystals. "Annalender physik", 1 Agost 2017, vol. 529, núm. 8, p. 1-4.