AOS recently completed and shipped a 610 mm 90-degree off-axis parabola to the Commissariat a l’Energie Atomique (CEA). The 8-meter focal length OAP will operate as the focusing element of the PETAL laser. The optic was fabricated and tested at or Durham Connecticut facilty and coated for high reflectivey and high damage threshold at Okamoto Optics in Japan.
This is the largest optic to date that AOS has produced with its newly developed process for producing low mid-spatial error in high performance aspheres. The parabola was fabricated using robotic polishing technology and coated with an advanced laser damage resistant dielectric mulitlayer coating. Specific technological hurdles to overcome during the fabrication of this element included high accuracy interferometry over an 8-meter test cavity.
Additional process engineering solutions we developed to minimize mid-spatial surface gradients to satisfy the power spectral desnisty requirements of CEA’s Laser MegaJoule (LMJ). This project demonstrated the scalability of AOS’s process for obtaining low gradient error results for high enegy density focusing optics.