STP1141

    Use of Dome (Meniscus) Lenses to Eliminate Birefringence and Tensile Stresses in Spatial Filters for the Nova Laser

    Published: Jan 1991


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    Abstract

    We document the concept and the design method for dome lenses that have a compressive pressure applied to the periphery. Dome (meniscus) lenses can eliminate both birefringence and tensile stresses if used in evacuated spatial filters where a pressure difference is present across the lenses. Calculations show that spatial filter birefringence is an insignificant 3 nm within the portion of a 740-mm Nova spatial filter dome lens illuminated by the laser beam. Membrane stresses are everywhere compressive, varying from -1.2 to -2.4 MPa, and are nearly uniform over the illuminated portion of the lens.

    Eliminating sources of birefringence on the Nova laser could increase the energy on target with Type II/Type II frequency conversion from ̃50% to the ̃70% level attainable with Type I/Type II frequency conversion. Eliminating tensile stresses may reduce the damage and catastrophic failure that has occurred in some Nova spatial filter input lenses. The major disadvantage of using dome lenses on Nova is the cost of new lenses which could range up to $50,000 per lens for the material and $20,000 per lens for finishing.


    Author Information:

    Pitts, JH
    Lawrence Livermore National Laboratory, Livermore, California

    Kyrazis, DT
    Lawrence Livermore National Laboratory, Livermore, California

    Seppala, LG
    Lawrence Livermore National Laboratory, Livermore, California

    Bumpas, SE
    Lawrence Livermore National Laboratory, Livermore, California


    Paper ID: STP23615S

    Committee/Subcommittee: F01.19

    DOI: 10.1520/STP23615S


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