Compact and accurate concept of laser wavemeters based on ellipsometry

Area of Science:

• Optics and Photonics
• Metrology
• Laser Physics

Background:

• Traditional laser wavemeters rely on scanning Michelson interferometers.
• These systems require large mirror displacements (tens of centimeters) for high accuracy (1x10^-6).
• Long displacements increase sensitivity to mechanical vibrations and beam misalignments.

Purpose of the Study:

• To demonstrate a new laser wavemeter concept.
• To utilize ellipsometric parameters (ψ and Δ) for wavelength measurement.
• To overcome limitations of traditional scanning interferometer wavemeters.

Main Methods:

• Measurement of ellipsometric parameters (ψ and Δ) of laser beams.
• Development of a polarimetric wavemeter.
• Experimental validation using an extended cavity laser diode (656 nm) and a Nd:YAG laser (532 nm).

Main Results:

• Achieved a relative accuracy of 1x10^-6 (1σ).
• Required a significantly reduced displacement range of only 4 μm.
• Demonstrated comparable performance to calibrated wavemeters.

Conclusions:

• The novel ellipsometric wavemeter concept is viable.
• This approach offers high accuracy with greatly reduced sensitivity to vibrations.
• The polarimetric wavemeter presents a compact and robust alternative for laser wavelength measurement.