Surface birefringence of self-assembly periodic nanostructures induced on 6H-SiC surface by femtosecond laser

- The birefringence effect of surface periodic nanostructures induced on 6H-SiC by femtosecond laser irradiation was reported.
- Birefringence characteristic can be controlled by single pulse energy and scanning velocity.
- ∼200 nm-Period deep-subwavelength periodic ripples (DSWR) are responsible for birefringence effect.
- The slow axis direction of DSWR was found to be always perpendicular to DSWR orientation, indicating form birefringence characteristics.
- A light attenuator based on DSWR structure was constructed and tested to have a tunable anttenuating ratio of 69-100% for 800 nm.