#Applied-Science #video on using Cloudray’s GM-100 US$7000 100-watt MOPA laser to engrave diffraction patterns (LIPS: laser-induced periodic structuring) and near-holograms on stainless steel with LightBurn. “MOPA” is “master oscillator power amplifier” and gives you a lot of control over the pulse power waveform from a fiber laser. He holds his too-thin stainless-steel sheets down with an aluminum vacuum chuck to get repeatable focusing, which doubles as a heatspreader and a heatsink. 300mm/s and 300kHz, thus 1μm pitch, worked well to get diffraction gratings, which he thinks are made of varying-thickness oxide layers changing the phase delay. He was using 45ns pulses at 19.6% power. He tried making optical #holograms: “How could you not do it after you realize you have full pitch and angle control over a #diffraction grating?”.
on 02025-10-15near-field #diffraction is "Fresnel diffraction" #optics
on 02025-08-24“homechemist” built a 2-nanometer spectral resolution #spectrometer using a DVD as the #diffraction grating and an old Canon DSLR
on 02022-05-21a 400× light microscope might reasonably be able to resolve 300 nm, just above the Abbe #diffraction limit for visible light. #optics #microscopes
on 02016-10-06