| 摘要 |
PROBLEM TO BE SOLVED: To provide a periodic structure forming method that can form a periodic structure reduced in deposition of debris with so-called a dry process without performing ultrasonic cleaning using a cleaning tank.SOLUTION: A periodic structure forming method includes a first step and a second step. The first step is configured by applying a pulse laser for the first step of a linear polarization with irradiation strength near a machining threshold value, performing scanning while making an irradiation portion overlap, and forming a grating-shaped periodic structure in a self-organized manner. The second step 22 makes the irradiation portion overlap with the pulse laser for the second step having a wavelength within ±10% and a pulse width of 50 picoseconds or less to the pulse laser for the first step in the first step. The irradiation energy per unit area in the second step 22 is set to become lower than that in the first step to perform scanning again. |
