펨토초 레이저에 의한 미세 회절패턴 제작

Diffractive patterning on metal thin film using femtosecond laser pulses

  Micromachining of metals with femtosecond laser has the different laser-matter interaction comparing to long pulse laser because there is not enough time during the femtosecond pulse for significant heat conduction to occur. We suggested the processing methods of the usage of mask which makes Gaussian spatial beam distribution to a normalized distribution by Fresenel diffraction, and fabricated the holography pattern generated by the IFTA algorithm on Cr thin film on glass substrate with a pixel size of 5×5 ㎛². We analysed the damage threshold with an assumption the power distribution as Gaussian profile as 45 mJ/㎠, This processing method is expected to get higher machining quality of metal film used in industrial fields such as 2-D bar code, MEMS patterning, mask repairing, etc.