Colloquium Lecture by Dr. Brandon Chalifoux

Space telescopes may one day perform astronomical imaging with micro-arcsecond angular resolution in optical or even X-ray wave bands, if ultralight mirrors and structures can be fabricated and aligned with sufficient accuracy. My group’s research aims to fabricate, align, and test thin lightweight optical components for a range of applications on Earth and in space.  

I will present an optical design form for diffraction-limited X-ray telescopes that could in principle enable micro-arcsecond angular resolution without deployable optics, albeit with a detector flying in formation. I will enumerate the opto-mechanical tolerances that would be required for such an optical assembly, and our research activities to address key challenges with mirror figuring, alignment, and testing of these thin acylindrical optical surfaces. I will present recent experimental results from our lab that demonstrate two techniques critical to this effort: (1) lateral shift mapping interferometry and (2) ultrafast laser stress strain generation for figuring and alignment of X-ray mirrors. Lateral shift mapping is a self-referencing metrology technique that we expect to be capable of measuring X-ray mirrors with nanometer-level RMS uncertainty, and we have built a testbed for testing and improving this technique. We have also built a system to focus an ultrafast laser, with sub-picosecond pulse duration, to generate strain in glass to bend substrates for figure correction, or to create dimensional changes for permanently adjusting mirror-to-mirror alignment. I will share our recent experimental results demonstrating the value of these techniques for future lightweight optics.