Compact implementation of a scanning transfer cavity lock

We describe an implementation of a scanning transfer cavity laser lock that is based on a commercial optical spectrum analyzer and an inexpensive computer microcontroller. The lock performs as well as a standard saturated absorption lock for frequency differences of several GHz. It offers the advantages of locking at arbitrary frequencies, having a large capture range, and allowing complex control mechanisms to be implemented via software. (c) 2005 American Institute of Physics.