blog posts Novel silicon etching technique crafts 3D gradient refractive index micro-optics Nov 28, 2016 8:00 amItems Share on Facebook Tweet Email Images Researchers at the University of Illinois have fabricated 3-D birefringent gradient refractive index (GRIN) micro-optics by electrochemically etching preformed Si micro-structures, like square columns, PSi structures with defined refractive index profiles. Share on Facebook Tweet Email