A reliable, compact, and low-cost Michelson wavemeter for laser wavelengthmeasurement

We describe the construction and operation of a simple, compact, and cost e ffective Michelson wavemeter with picometer accuracy. The low cost of the d evice means that it can form the basis of an undergraduate laboratory exper iment, yet it is sufficiently reliable and accurate that it has become an i mportant tool in our research laboratory, where it is regularly used to tun e lasers to atomic transitions. The usefulness and accuracy of the wavemete r is demonstrated by tuning two separate extended cavity diode lasers to ac hieve two-step excitation of the Rb 5(2)D state, observed by detecting 420 nm blue fluorescence from the 5(2)D-->6(2)p-->5(2)S decay path. (C) 1999 Am erican Association of Physics Teachers.