The 771 Laser Spectrum Analyzer is a very unique instrument that operates as both a high-accuracy wavelength meter and a high-resolution spectrum analyzer. Laser wavelength is determined to an accuracy as high as ± 0.2 parts per million. And, with a spectral resolution as high as 2 GHz and an optical rejection ratio of > 40 dB, the system provides the most detailed information about a laser’s spectral properties. Two versions of the model 771 are available. The 771A is offered for the most demanding experiments, measuring laser wavelength to the highest accuracy of ± 0.2 parts per million (± 0.0002 nm at 1000 nm). For experiments that are less exacting, the 771B is a lower-priced alternative, measuring laser wavelength to an accuracy of ± 0.75 parts per million (± 0.0008 nm at 1000 nm). These specifications are guaranteed by continuous calibration with a built-in wavelength standard, thereby ensuring the most meaningful experimental results. The model 771 is available in several broad wavelength configurations to satisfy virtually any experimental requirement. These are the VIS (375-1100 nm), NIR (520-1700 nm), IR (1-5 µm), and MIR (1.5-12 µm). The laser under test enters the VIS and NIR systems through a pre-aligned fiber-optic input to ensure optimum alignment. The laser under test enters the IR and MIR systems through a free-space aperture, through which the internal HeNe reference laser is emitted as a visible tracer beam to facilitate alignment. The 771 Laser Spectrum Analyzer operates with a PC, running under Windows, via USB or Ethernet interface. Software is provided to control measurement parameters and to display spectra and to report wavelength data. Or, the system can become part of an experiment using a library of commands for custom or LabVIEW programming.