Optical fabrication

1. Fabrication of  Super smooth optical surfaces:

     High energy lasers require mirrors and optical windows with very high reflectivity and high transmission, respectively, and with reasonably high Laser Induced Damage Threshold (LIDT).  To achieve this the substrates should have ultra-low surface roughness (Super smooth) below 5 Å with minimum cosmetic defects apart from a high degree of surface flatness. ODDL has augmented a super-smooth optical polishing facility using Bowl-feed technique.
   
   

   
   Photograph of Bowl-feed polishing

2. Fabrication of Nd: Glass Laser Rods

   ODDL developed technique for fabrication of Nd: Glass laser rods from raw Nd: glass slabs. The fabrication involves number of machining operations such as, sawing/cutting, milling, and rounding. The flat end surfaces of the fabricated rods are grinded and polished to required optical finish and parallelism for end use.
   

   
   Photograph of Nd: Glass laser rod fabrication

3. Fabrication of large size Nd: glass (Phosphate) discs:
   
   Nd: glass slabs are used in disc amplifiers of Nd: glass laser systems. Un-polished raw Nd: glass discs have typical dimensions of 300 mm x 150 mm x 50 mm.  Technique for polishing such large Nd: glass discs surfaces has been developed using conventional grinding and pitch polishing. Required mechanical fixtures and holders were designed and fabricated to achieve a good surface flatness of the order of λ/10 (λ @589.3 nm) over 100 mm diameter. In addition, a new double side optical polishing facility has been setup. Here, 3 numbers of 400 mm diameter flat optics can be simultaneously polished on both sides.
   

   
   
   Photograph of Un-polished and polished Nd: glass discs

   Machines available at ODDL for the fabrication of optical components:
   
   Glass Sawing Machine                    Glass Milling Machine                  Glass Edging Machine
   
   
   Glass Trepanning Machine                Double Side Polishing Machine      Cylindrical polishing machine
   

   Optical components fabricated
   

   
   Prisms, Corner Cube, Dye cell window, Polished Metals, Cylindrical optics, Silicon wafer