Fabrication and assembly of grazing-incidence X-ray telescope optics using ultrafast laser processing (B Chalifoux, UoA)

Title: Fabrication and assembly of grazing-incidence X-ray telescope optics using ultrafast laser processing

Speaker: Dr. Brandon Chalifoux, University of Arizona (Tucson, AZ – USA)

Date: Friday, January 23 – 11am

Location:  Building 2 room 400 (zoom link)

Host: Antoine Islegen-Wojdyla (Advanced Light Source/Berkeley Lab)

Description: The future of high-energy astrophysics depends on having instruments with much higher angular resolution and throughput than is possible with current mirror fabrication technology. Building a telescope with large effective aperture area requires thin mirrors, and high angular resolution requires nanometer-scale surface height errors, resulting in a severe optomechanical challenge. We are developing a novel process for fabricating and assembling X-ray telescope mirror modules, which we call Flex Modules. The key distinction from prior art is that our process delays mirror figuring and alignment of each mirror until it has already been coated and bonded onto the module, using a process called Ultrafast Laser Stress Figuring (ULSF). ULSF focuses ultrafast laser pulses into the glass mirror substrates, from the uncoated backside, to generate deterministic stress that bends the mirror with nanometer-scale precision. The Flex Module process also uses ultrafast laser pulses to form flexure-supported mirrors (reducing mounting-induced deformation and enabling adjustable alignment), and to weld each mirror onto the module. I will present our early process development results and our plans to advance this process toward fabricating high-resolution mirror modules. Ultimately, future large X-ray telescopes will require a manufacturing process capable of meeting the stringent figure, mid-spatial frequency, and surface roughness requirements for thousands or tens of thousands of mirrors, and the Flex Module approach has great potential to meet these future needs.