New invisibility concept and miniaturization of photonic circuits using ultrafast laser
From compact biosensors and spectrometers to invisible devices and quantum computers, applications related to integrated photonics are increasingly sought after. As in optical fibres, guiding light in integrated photonic circuits is achieved by a local increase of the refractive index (RI) of the material. Ultrafast laser writing is the only technology that allows three-dimensional RI modification in transparent materials, thus the direct fabrication of 3-D photonic devices. Following the first laser writing of photonic channels in glass in the late 90s, it was believed that the technology would quickly become the tool of choice for the manufacture of integrated photonics. However, despite numerous efforts, the magnitude of the laser-induced RI change remains limited, preventing the fabrication of compact devices with bendy optical channels which require high RI changes.