Martínez Matos, ÓscarCalvo Padilla, María LuisaCheben, PavelMonte Muñoz de la Peña, Francisco delRodrigo Martín-Romo, José Augusto2023-06-202023-06-202006-08-250031-900710.1103/PhysRevLett.97.084801https://hdl.handle.net/20.500.14352/51022© 2006 The American Physical Society. We thank G. F. Calvo for helpful discussions. Partial financial support from the Spanish Ministry of Education and Science through Projects No. TEC2005-02180 and No. MAT2003-02718 is gratefully acknowledged.We report observations of periodic oscillatory behavior of the angular selectivity, near the Bragg angle, in volume holographic gratings recorded in a new photopolymerizable glass with high refractive index modulation. We have detected the presence of overmodulation in the intensity distribution of the first diffraction order. The results reported here were achieved by incorporating in the photopolymerizable sol-gel glass zirconium-based high refractive index species at the molecular level. This is the first time that this effect is observed for light diffraction in an amorphous material.engjournal articlehttp://dx.doi.org/10.1103/PhysRevLett.97.084801http://journals.aps.orgopen access535Orbital Angular-MomentumWave-Front ConversionCylindrical PhaseVolume HologramsGaussian-BeamPlane-WaveDiffractionEntanglementCrystalsGratingsÓptica (Física)2209.19 Óptica Física