Wide-field polarimetric second harmonic imaging for rapid and non-destructive investigation of laser-induced crystallization phenomena

The selective and controlled formation of nanocrystals in glass is emerging as a versatile method to achieve functional photonics, opto-electronics and quantum devices, such as single photon emitters. In this context, we investigate the use of wide-field polarimetric Second Harmonic (SH) microscopy as a method to rapidly and non-destructively examine nanoscale crystal arrangements in laser-processed glass. As a case-study, we investigate tellurite glass, where the formation of a trigonal tellurium (t-Te) nanocrystalline phase after femtosecond laser exposure was recently demonstrated. Combined with theoretical models, we show that wide field polarimetric SH microscopy offers comprehensive information on the nanocrystals’ orientation, distribution and chirality. Furthermore, we examine the effect of composition ratio of tellurite-based glasses on the degree of t-Te crystallization. With its high imaging throughput and spatial resolution, this method has the potential not only to significantly accelerate investigations on laser-induced glass-crystallization processes, but also to provide a valuable tool for in situ process monitoring.