Fabrication of meter-scale laser resistant mirrors for the National Ignition Facility: a fusion laser

Stolz, Christopher J.; Weinzapfel, Carolyn L.; Rigatti, A. L.; Oliver, J. B.; Taniguchi, Jason; Bevis, Ron P.; Rajasansi, Jasbir S.

doi:10.1117/12.511677

Cited by 19 publications

(10 citation statements)

References 12 publications

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“…Multi-layer high-reflectivity dielectric coatings deposited on BK-7 substrates serve as mirrors throughout the NIF. The coating layers are HfO 2 /SiO 2 deposited by e-beam evaporation [6][7][8] . The mirrors are installed in two main locations on the NIF.…”

Section: Overview Of the Nif Optical Layoutmentioning

confidence: 99%

NIF optical materials and fabrication technologies: an overview

et al. 2004

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The high-energy/high-power section of the NIF laser system contains 7360 meter-scale optics. Advanced optical materials and fabrication technologies needed to manufacture the NIF optics have been developed and put into production at key vendor sites. Production rates are up to 20 times faster and per-optic costs 5 times lower than could be achieved prior to the NIF. In addition, the optics manufactured for NIF are better than specification giving laser performance better than the design. A suite of custom metrology tools have been designed, built and installed at the vendor sites to verify compliance with NIF optical specifications. A brief description of the NIF optical wavefront specifications for the glass and crystal optics is presented. The wavefront specifications span a continuous range of spatial scale-lengths from 10 µm to 0.5 m (full aperture). We have continued our multi-year research effort to improve the lifetime (i.e. damage resistance) of bulk optical materials, finished optical surfaces and multi-layer dielectric coatings. New methods for post-processing the completed optic to improve the damage resistance have been developed and made operational. This includes laser conditioning of coatings, glass surfaces and bulk KDP and DKDP and well as raster and full aperture defect mapping systems. Research on damage mechanisms continues to drive the development of even better optical materials.

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Section: Overview Of the Nif Optical Layoutmentioning

confidence: 99%

NIF optical materials and fabrication technologies: an overview

et al. 2004

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“…Meanwhile, the mid-frequency surface shape of the elements is also of concern in NIF. 6,17 And higher spatial resolutions surface information could be obtained by subaperture stitching than by the other two methods. However, the efficiency of the subaperture stitching method is always criticized especially when the number of the subaperture is very large.…”

Section: Introductionmentioning

confidence: 99%

“…17,18 The relative motion track is always rotationally symmetrical in ring polishing and the amount of material removal is related to the radius. Thus, the height errors are identical when the points are in the same radius, [19][20][21] which can largely reduce the coverage area when the subaperture stitching method is used to measure the figure error of the surface.…”

Section: Introductionmentioning

confidence: 99%

Sparse subaperture stitching method for measuring large aperture planar optics

Shen

Tong

et al. 2016

Opt. Eng

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Abstract. Ring polishing is a primary method to polish large aperture planar optics that is widely used in the fabrication of high-power solid-state laser equipment. The relative motion track with the ring polishing is always rotationally symmetrical and the amount of material removal is related to the radius. The height errors are identical when the points are in the same radius, which can largely reduce the coverage area when the subaperture stitching method is used to measure the figure error of the surface. A new sparse lattice for planar optics polished by ring polishing is introduced. The cumulative error is proven small enough for sparse subaperture stitching by the reference of the simulated data. A planar optical element with 200 mm × 200 mm aperture was chosen to test the feasibility of our proposed method. The results indicate that sparse stitching is suitable for measuring a large planar surface polished by ring polishing. The results of two chain lattice are closer to the fully covered lattice than a one chain lattice. However, more measuring time could be saved by the one chain lattice method. So, the usage of different lattices could be adapted for different periods of large aperture planar optical manufacturing. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…These optics are manufactured by vendors in the private sector that have partnered with LLNL to develop technologies needed to meet our specifications and manufacturing rates to complete the NIF laser by 2008. [1][2][3] Dielectric coated multilayer mirrors on BK7 substrates are used to steer the beams through the laser beampath and into the target chamber. To maintain the focussability of the beam in the target chamber center, the optics must add minimal wavefront distortion (<7 nm/cm RMS gradient) to the laser beams.…”

Section: Introductionmentioning

confidence: 99%

Metrology of mirrors for the National Ignition Facility

et al. 2004

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The large-aperture (up to 40 cm × 80 cm) mirrors required for the National Ignition Facility have very stringent specifications. The specifications include requirements for transmitted and reflected wavefront over a wide spectral frequency, surface quality, laser resistance, spectral characteristics, etc. In order to validate optic performance, metrology tools were fielded at optic fabrication vendors to assure production control. These tools include interferometers, largearea conditioning stations, and photometers. Of the 1800 large-aperture mirrors required for the NIF, approximately 35% have been completed. This presentation will review the types of large-aperture mirrors used on NIF along with the performance of NIF optics as measured and received from our vendors.

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Fabrication of meter-scale laser resistant mirrors for the National Ignition Facility: a fusion laser

Cited by 19 publications

References 12 publications

NIF optical materials and fabrication technologies: an overview

NIF optical materials and fabrication technologies: an overview

Sparse subaperture stitching method for measuring large aperture planar optics

Metrology of mirrors for the National Ignition Facility

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