A pressure-tuned Fabry Pérot interferometer for laser frequency stabilization and tuning

We present a simple, inexpensive pressure-tuned Fabry Pérot interferometer which can be used to frequency stabilize and tune a laser when no suitable atomic reference is available. Our design, made largely from off-the-shelf parts, yields a tuning range of about 4 GHz and offers an absolute tuning accuracy of better than 1 MHz. The interferometer, which uses air as its working medium, is characterized by a low thermal drift rate of order 1 MHz per hour.