Etaloning Laser Interference Analysis Spectrometry (ELIAS)

Many fields of research require precise wavelength measurement, but commercially available wavemeters are often too expensive, too large, or too fragile to be practical. We have designed and constructed a robust, compact, and inexpensive wavelength meter that analyzes the interference patterns caused by a series of etalon-like structures. Measuring this etaloning across a range of known wavelengths provides a set of wavelength-dependent reference functions which can be used to calculate an unknown wavelength within the same range. We present data showing that this device can measure a laser's wavelength with an average error less than a picometer, and a standard deviation less than 2 picometers.