Laser Haunted House

LaserFest was a major participant in the USA Science and Engineering Festival, which attracted an estimated half-million visitors to the Mall in Washington over the weekend of October 23-24. Working with the Society of Physics Students, the American Institute of Physics, the American Association of Physics Teachers, and OSA, APS created the "Laser Haunted House" with several laser demos embedded in a Hallowe'en-themed setting. Thousands waited patiently for their chance to see and play with the lasers inside. In the photo, APS LaserFest Coordinator James Roche demonstrates the "squealing wall", in which a laser beam, reflected off a mirror and coupled to a solar cell and speaker, produces eerie sounds due to the interference of the beam with itself.