Extremely demanding Gaussian Reflectivity Mirror (GRM) for Commercial application

  • First side of 1” diameter GRM the Gaussian profile coating must occupy the full surface

  • Second side of GRM must have a tri-wavelength design dielectric coating

  • GRM must have an extremely high laser damage threshold coating of 5J/cm² for 1ns

  • Solution required super polish for surfaces, advance cleaning methodology, new coating materials and redesign of mask design software

  • BMV met the customers specifications and exceeded the required laser damage threshold

Tetrahedron Prism

  • Prototype with an eventual commercial application

  • Material is crystal quartz with the axis orientation tightly controlled

  • 14 polished surfaces

  • All dimensions accurate to 50µm

  • All angles accurate to 1 arc minute

Complex Glass Machining

  • Space bound optic for the International Space Station

  • Holes on each side must be aligned precisely with holes on opposite side

  • Because of large number of holes diamond wear on the drill was a serious problem in order to maintain very tight tolerance on diameter and depth of holes and hole position

  • Extremely time consuming alignment procedure and drilling of holes. Extremely time consuming metrology with CMM.

  • Material is high purity Fused Silica

  • Bi-Convex lens with each radius of curvature accurate to 1%

  • 200 blind drilled holes per side

  • All hole diameters, spacing, depth and placement relative to a reference, accurate to 50µm

Axicon Project

  • Customer Axicon Requirements Included:

    • Precise Apex Angle (Tolerance = +/-0.1Degrees)

    • Minimal decentration (Tolerance = +/-0.010mm)

    • Extremely small Apex Rounding Diameter (>1.5mm)

    • Two-sided broadband visible AR coating.

  • Special Design Considerations Included:

    • Specialized high-speed part holder and blocking component had to be manufactured to ensure part decentration and Apex Angle specifications were still met under high lateral polishing forces.

    • Part surface generation was made to a pre-polish quality to decrease the amount of total polishing time necessary, which was found to decrease overall surface zoning.

    • High-speed equipment modifications had to be made to ensure that the software limitations of the machine wouldn’t result in uneven surface working conditions during Axicon polishing.

  • Unexpected Issues Included:

    • Conventional polishing pad materials and configurations lead to badly damaged Apex tip.

    • A non-conventional polishing pad shape was created to polish the Axicon surface in concert machine software modifications to prevent damage and Apex rounding from occurring to the Apex tip region.