Measuring UV-Lasers in focus within a few seconds basis for laser micro manufacturing

Abstract

In general, micro machining with lasers requires very small spots. With standard beam diagnostic systems therefore it is difficult to qualify the processing tool. Additionally, very often these processes are designed to operate in the UV, while standard CCD camera systems are optimized for visible radiation at low power only.We will discuss important effects that have to be taken into account to run a successful measurement of the focus of a high power laser beam on a micrometer scale at a wavelength shorter than 400 nm.Some of the items that will be addressed are: • Spectral sensitivity of the CCD and radiation induced damage • Direct usage of CCD or fluorescence conversion • Transmission within the optical beam path of the measuring device • Integrated mechanical set-up and data transmission for a fast caustic measurement As a possible solution a new camera based focal diagnostic system is presented. This system enables the measurement of the power density distribution of UV-laser spots down to several microns.In general, micro machining with lasers requires very small spots. With standard beam diagnostic systems therefore it is difficult to qualify the processing tool. Additionally, very often these processes are designed to operate in the UV, while standard CCD camera systems are optimized for visible radiation at low power only.We will discuss important effects that have to be taken into account to run a successful measurement of the focus of a high power laser beam on a micrometer scale at a wavelength shorter than 400 nm.Some of the items that will be addressed are: • Spectral sensitivity of the CCD and radiation induced damage • Direct usage of CCD or fluorescence conversion • Transmission within the optical beam path of the measuring device • Integrated mechanical set-up and data transmission for a fast caustic measurement As a possible solution a new camera based focal diagnostic system is presented. This system enables the measurement of the power density distribution of UV-laser spots down to several...