Shanghai Optoelectronics made progress in ultrafast laser-induced supercontinuum birefringence

[ Instrument R&D ] Recently, the laser micromachining research team of the State Key Laboratory of Strong Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences has made progress in ultrafast laser-induced supercontinuum birefringence of isotropic materials. The team found that the supercontinuum generated by the interaction between ultrafast laser and quartz glass has a birefringence effect, which originates from the anisotropic microstructure induced by ultrafast laser. Related research results were published in "High Power Laser Science and Engineering" (High Power Laser Science and Engineering).

Ultrafast laser interacts with transparent materials to produce white light supercontinuum. This supercontinuum is similar to laser. It has the characteristics of high brightness, good directivity and good coherence. It is used in frequency measurement, optical coherence tomography and time-resolved spectroscopy. And other important applications.

The research team found that the supercontinuum generated by the interaction between ultrafast laser and quartz glass has a birefringence effect, and the birefringence intensity of the supercontinuum shows a growth-saturation characteristic with time. As the ultrafast laser power increases, the birefringence intensity of the supercontinuum increases accordingly. Through time-resolved morphology, it was found that the birefringence effect was caused by the anisotropic microstructure induced by ultrafast laser in quartz glass. The laser-induced anisotropic microstructure area gradually increases with the time of the laser action, and at the same time, the supercontinuum spectrum is modulated in real time, so that the birefringence intensity of the supercontinuum spectrum gradually increases and reaches saturation state with time. This work can effectively deepen the cognition of the mechanism of supercontinuum interaction between ultrafast laser and isotropic materials, which is expected to expand the supercontinuum spectrum.

Related work has been supported by the National Key Research and Development Program (2016YFB1102402) and the National Natural Science Foundation of China (61675214).