Laser Wavelength Measurement Based on a Digital Micromirror Device

We constructed a relatively simple inexpensive wavemeter with completely static parts to measure the laser wavelength accurately based on diffraction from a Fresnel zone plate (FZP) displayed on a digital micromirror device. The unknown laser wavelength was measured by finding the proper FZP, focusing the laser beam exactly into the specified focal point. The relative uncertainty in the order of 10
^-5
was attained in He:Ne and second harmonic of Nd:YAG laser wavelength measurement.