题 目：DUV coating/bulk absorption measurement using LID technique
报告人：Christian Mühlig（Institute of Photonic Technology Jena,Germany）
In this presentation the laser induced deflection (LID) technique is introduced which belongs to the manifold of photo--‐thermal absorption measurement techniques. Unlike most techniques the LID concept is based on a transversal pump/probe beam arrangement. Besides explaining different measuring concepts the presentation will show how the transversal pump/probe beam setup allows for an absolute (electrical) calibration concept that is unique for photo--‐thermal techniques since it provides absolute absorption data without the knowledge of photo--‐thermal material parameters (and simulations). Unlike other techniques the LID technique can be applied to any laser/wavelength with no restrictions to the laser beam parameters (M2, pulsed, cw…). Therefore it is potentially suited to investigate the absorption of thin films and bulk materials at common DUV excimer laser wavelengths.
The talk will show an overview of recent investigations of DUV coatings and thin films at 193nm using the LID technique. The experiments range from single layer measurements to polarization and AOI dependent measurements of highly reflecting mirrors. Furthermore, a concept is suggested to yield information about interface/surface engineering and it is shown how the combination with laser--‐induced fluorescence can identify critical residual impurities in fluoridic thin films for 193nm applications.