We show how the cross-over effect of dipolar glasses can be used to observe diffraction cancellation in composite ferroelectric samples independently of composition. We are able to selectively frustrate the dielectric anomaly of different compositionally disordered photorefractive ferroelectrics to achieve scale-free optical propagation at one same temperature.
Bibliographical noteFunding Information:
We thank M. Deen Islam and G. Bolle for technical assistance. This work was supported by funding from the Italian Ministry of Research (MIUR) through the “Futuro in Ricerca” FIRB grant PHOCOS-RBFR08E7VA and from the European Research Council under the European Community Seventh Framework Program (FP7/2007-2013)/ERC Grant Agreement No. 201766. Partial funding was received through the SMARTCONFOCAL project of the Regione Lazio and through the PRIN Project No. 2009P3K72Z. A.J.A. acknowledges the support of the Peter Brojde Center for Innovative Engineering.