Application of adaptive optics to laser micromachining

Abstract

For many laser machining applications it is common to use some form of beam shaping to modify the typically Gaussian intensity distribution of the laser to generate an intensity profile that is more appropriate for the task. For example refractive elements may be used to generate top hat intensity distributions which are better suited to drilling applications or more complex profiles may be generated to mark patterns on a surface either with diffractive elements or masks. Dynamic beam shaping elements offer an advantage in terms of changing between shapes rapidly to quickly mark a series of shapes across a surface or even to modify the beam shape during a machining operation.Machining demonstrations are presented with two types of adaptive optics (AO’s) using millisecond and nanosecond pulsed lasers. The first AO is a piezoelectric deformable mirror capable of supporting high average powers and enabling rapid (∼1 kHz) modification of the mode shape of a beam. The second is a liquid crystal spatial light modulator which, although slower in response (75 Hz), can generate complex arbitrary shapes. The dynamic nature of these elements is used to improve the quality of laser machining results.For many laser machining applications it is common to use some form of beam shaping to modify the typically Gaussian intensity distribution of the laser to generate an intensity profile that is more appropriate for the task. For example refractive elements may be used to generate top hat intensity distributions which are better suited to drilling applications or more complex profiles may be generated to mark patterns on a surface either with diffractive elements or masks. Dynamic beam shaping elements offer an advantage in terms of changing between shapes rapidly to quickly mark a series of shapes across a surface or even to modify the beam shape during a machining operation.Machining demonstrations are presented with two types of adaptive optics (AO’s) using millisecond and nanosecond pulsed lasers. The first AO is a piezoelectric deformable mirror capable of supporting high average powers and enabling rapid (∼1 kHz) modification of the mode shape of a beam. The second is a liquid crystal spatial light m...