Authors:
            
                    Sebastian Buettner
                    
                        
                    
                    ; 
                
                    Michael Pfeifer
                    
                        
                    
                     and
                
                    Steffen Weissmantel
                    
                        
                    
                    
                
        
        
            Affiliation:
            
                    
                        
                    
                    Laserinstitut Hochschule Mittweida, Technikumplatz 17, Mittweida, Germany
                
        
        
        
        
        
             Keyword(s):
            Fluorine Laser, Fused Silica, Microstructuring, Orbital Angular Momentum, Spiral Phase Plates.
        
        
            
                
                
            
        
        
            
                Abstract: 
                The results of our investigations on direct laser fabrication of micro spiral phase plates (SPPs) in fused silica using the fluorine laser microstructuring technique will be presented. The process, which based on the mask projection technique, enables the generation of SPPs with different topological charges, handedness, modulation depths and level numbers. For this, a special double mask rotation system was developed, which allows the fabrication of micro SPPs with an individual configuration with regard to the mentioned parameters. Moreover, the phase of a spherical lens can be added to the helical phase of the SPP using a special mask geometry. Furthermore, we build up a measurement system for a first optical characterization of the fabricated SPPs.