Evolution of self-organized nanograting from the pre-induced nanocrack-assisted plasma–laser coupling in sapphire

Formation of nanogratings driven by ultrafast laser irradiation in mid-IR heavy oxide glasses

“…Recently, Wang et al [14] and Sakakura et al [15] reported a new intermediate regime called type X modification (randomly distributed anisotropic nanopores induced by ultrafast laser), which is regarded as the early structure of NGs and can be used for ultralow-loss birefringence devices. NGs induced in volume and by fs laser were observed on several glasses or crystals among which we can cite GeO2 glass [16][17][18], TeO2 single crystal [19], Sapphire [20], Al2O3-Dy2O3 binary glass [21], lithium niobium silicate glass [22] or titanium silicate glasses (ULE, Corning) [23] and even in multicomponent aluminoborosilicate glasses (Borofloat 33, Schott) [23]. The silicate ones [24], are the most ubiquitous glasses employed for femtosecond laser direct writing (FLDW), as they are readily commercially available and offer both excellent optical transparency and physico-chemical stability.…”

Research advances of femtosecond laser-induced nanogratings for transparent materials

“…In addition, they achieved the erasure and rewriting of nanogratings by using two orthogonally polarized femtosecond laser pulses. This study provides new evidence for the physical mechanism of laser-induced nanogratings and paves the way for the preparation of sapphire substrate nanodevices ( Zhai et al, 2021 ).…”

“…As with glass materials, the study of factors influencing the internal nanograting structure of sapphire is also a popular topic. In 2021, Zhai et al (2021) found that the overall structure of the nanogratings shrank and narrowed as the scanning speed increased, and individual nano cracks with widths below 100 nm were prepared after acid etching. As the laser fluence increased, nanogratings expanded and increased in number, and the period varied between 320 and 398 nm.…”

Effect of Pulse Repetition Rate on Ultrafast Laser-Induced Modification of Sodium Germanate Glass

“…Similar nanogratings formed by layers of oriented LiNbO 3 nanocrystals were shown in lithium niobium silicate [ 29 , 30 ] and lithium niobium borosilicate [ 31 ] glasses. Appearing to be a common phenomenon for oxide dielectrics, nanogratings were also inscribed in single crystals such as quartz [ 32 ], sapphire [ 33 ] and Nd:YAG [ 34 ]. In the case of YAG (Y 3 Al 5 O 12 ) crystal, their formation was shown to originate from the phase transformation rather than nanopore emergence, and the nanoplanes were formed via Y 3 Al 5 O 12 amorphization or recrystallization into a perovskite-like phase depending on laser writing conditions [ 34 ].…”