Transmitting audio over a laser pointer using amplitude modulation is pretty easy to do, however it is susceptible to all manner of interference. The LASER transmitter/receiver project by Samer Muhi takes this to the next level by using frequency modulation to reduce the amount of interference caused by ambient light and changes in transmitter intensity.
This project demonstrates the use of laser in optical communications. the project consists of a transmitter and receiver that will support a one-way communications link between two separate locations. It is mainly built from a few ICs, operational amplifiers and transistors. It is possible to transmit music, voice and data. The laser used in the transmitter is a simply a laser diode that it used in cheap laser pointers and at the receiver, the laser sensor is a photo-diode.
[via hacked gadgets]