双光束飞秒激光干涉在6H-SiC表面制备亚微米坑阵列及其光吸收增强

We report the fabrication of submicrometer pits array (SP-array) on 6H-SiC surface by the interference of two femtosecond laser beams. Formation mechanisms and optical absorption of SP-array are studied. The relative reflectivity and transmissivity of white light decrease to 10% of the values of SiC crystal, and the optical absorption is enhanced to 97%. The relative reflectivity and transmissivity of incident angles within the range of 20o~60o are kept below 25%. The enhancement mechanism of optical absorption of the SP-array is also discussed.