Meadowlark Optics is proud to announce that a collaborative project with Lawrence Livermore National Laboratory has won a prestigious R&D 100 award!
The LEOPARD system installed on the laser system of the National Ignition Facility consists of 48 Programmable Spatial Shapers that were developed to shadow point defect flaws in the main laser optics and arrest fluence-dependent damage growth at those locations. Meadowlark Optics was critical in developing assembly and qualification methods for the fragile photoconductive materials needed to construct the Optically Addressable Light Valve at the heart of each shaping device.
The valves are addressed with an incoherent blue light pattern that is projected onto the photoconductor layer, raising its conductivity where light is present. Through a voltage divider, this produces a spatially modulated electric field which in turn controls the retardance of a twisted nematic liquid crystal layer. The liquid crystal layer then imprints the pattern onto the coherent infrared laser beam just before it is amplified to produce the world’s most energetic laser system.
Because of the nonpixelated nature of the valves, they can be used to create extremely smooth beam shapes, free of artifacts typically found in many commercial modulators. As a result, the LEOPARD system also enables high energy laser systems to be optimized by decreasing the beam intensity variations (hot spots* in particular) that can lead to intensity-dependent filamentation damage.
*Hence the name: Laser Energy Optimization by Precision Adjustments to the Radiant Distribution (LEOPARD)
The image below is an actual leopard image imprinted on a high power beam with LEOPARD (without spatial filters that would blur it) and without post processing the image other than representing the camera recorded fluence distribution with a red color map.