High Order Diffraction Suppression of the Membrane with Hexagonal Hole Array Topics: Applied Industrial Optics; Biomedical Optics; Optical Instrumentation; Optics in Astronomy and Astrophysics; Spectroscopy, Imaging and Metrology In Proceedings of the 5th International Conference on Photonics, Optics and Laser Technology PHOTOPTICS - Volume 1, 59-64, 2017 , Porto, Portugal