Michelson Interferometer

thingiverse

A basic Michelson Interferometer for demonstration purposes. SAFETY WARNING: Exercise caution when working with the laser and arduino. Avoid direct eye contact with the laser during construction and operation of the interferometer. Materials: 1. Enhanced Aluminum Mirror 25 mm - 2 x $20.50, available from Edmund Optics 2. 50:50 Plate Beam Splitter 25 mm - 1 x $42.00, also from Edmund Optics 3. MakerBeam T-Slot Aluminum Beams 4 Pack - 300 x 10 x 10 mm - 1 x $12.56 4. GeeBat Laser Dot Diode - 10 pack, 650 nm, 5 mW - 1 x $5.29 5. Arduino - Elegoo UNO R3 - 1 x $11.98 6. M2.5x6 or M3x6 Screws* - 10 x $0.00; M2.5x20 or M3x20 Screws* and Associated Bolts - 6 x $0.00 Code: void setup() { // initialize digital pin 13 as an output. pinMode(13, OUTPUT); } // the loop function for continuous laser beam operation void loop() { digitalWrite(13, HIGH); } Construction Procedures: Steps: 1. Initiate the process by 3D printing all parts with a 0.1 mm layer height, 10% infill, and 2 shells. Ensure thorough post-production work to achieve smooth surfaces that can accommodate necessary components. Test mirror mounts with an object of similar size for proper fitment, avoiding potential surface scratches. 2. Attach each t-slot aluminum beam to the connector/beam splitter using 8 M2.5X6 screws (note: this construction uses 4 M2.5X8 screws). 3. Feed a laser diode through the laser diode mount and attach it to one end of an aluminum beam with two M2.5x6 screws. The distance from the end is arbitrary, approximately 1 1/2 inch. Connect the red/hot wire to the 13 port on the digital side of arduino and the blue/ground wire to the GND port next to it. Plug the arduino into a computer, and use the provided code to power the laser. Note: It's essential to test each laser for defects by powering it on, unfocusing it, and observing which laser has the least number of spots. 4. Remove the cap from six small springs in the laser diodes. Set up the mirror mount in the front-to-back order shown in the photo. First place the mirror into the holder (fourth from left), then cover it with the top piece (second from left). Screw the M2.5x20 screws through. Flip the object over and attach a spring to each prong, feeding it into the final piece and screwing on the bolts as seen in photos. 5. Attach the mirror mounts to aluminum beams approximately 1 inch from the end, aligning them with the orientation shown in the photo. Pay close attention to the angle of the beam splitter holder relative to the laser, as it may be opposite. Position the beam splitter and note: Be cautious when moving or adjusting the device, as the mirrors and beam splitter can fall. 6. In a dark room, power the laser on. Adjust the laser diode's position within its mount so that its light passes directly through the center of the beam splitter and hits the center of the opposite mirror. Adjust the beam splitter to direct light towards the center of the adjacent mirror. 7. With light blocked from the adjacent mirror, use the bolts in the back of the mirror opposite from the diode to adjust the light until it reflects as close as possible to the diode without overlapping its source. Use notecards or folded paper to block the light and observe the reflection. 8. Remove the paper blocking the light from the adjacent mirror and place it onto an aluminum beam with no parts attached. The beams should not be aligned, as represented in the photo. If only one beam is present, this may indicate that the adjacent beam is off focus; adjust the bolts until both beams are visible. 9. Only adjust the mirror adjacent to the laser until the two sources overlap to produce fringing patterns, as seen in photos. When the table is tapped with a closed fist, the fringing patterns will disappear.