Download High Res. About 770kB
With slightly different contrast settings
Diagram of setup to produce the above pictures. Used a Dremel tool and #79 (400mm) drill bit to drill a hole in a 5x10x0.5mm sheet of brass. Sanded with #600 grit Wet or Dry sand paper to debur the hole. Cleaned the hole with 95% ethanol and examined it under a stereo microscope to make sure it was clean and burr free. A 1/8” Dia. S.S. ball bearing was cleaned in ethanol and examined under the microscope until clean. A high quality Cyanoacrylate glue was used to attach the ball to a clean microscope slide. I put a #1 and a #0.5 aluminized neutral density filters in front of the laser to make it safe for alignment and centered the pinhole in the diode laser beam. The distance between the pinhole and the ball bearing was adjusted so that the central diffraction spot is the same diameter as the ball bearing. (About 180cm in my setup.) A a millimeter scale was printed onto drafting Vellum and glued to a 2”Dia x ¼” thick aluminum ring. The Poisson spot was photographed from the location shown using a Pentax Optio S5i digital camera.
