Abstract A device is described which yields an inexpensive and simple to construct modulator, which is used in conjunction with a CO₂ laser. Results of using a germanium PIN diode to modulate the 10.6 μm radiation are given. An attempt to measure deflection of the laser beam using the modulator is also described. Finally measurements of percentage modulation versus position of the laser beam are presented in a series of curves. The results of the experiments show that this...