Calibration of laser interferometer at The National Laboratory

Purpose

The national laboratories are responsible for maintaining the national reference standards for each measurement quantity and spreading metrological competence and traceability to industry and society at large. The national reference standards are the highest level of traceability in Sweden.

A calibration performed at a national laboratory fulfils all typical traceability and accreditation requirements that commonly exist in industry and society at large. 

Method

Calibration of the object’s laser frequency is performed via heterodyne measurement against one of Sweden’s primary standards for optical frequency. The standards are Iodine-stabilized He-Ne lasers with a laser frequency in agreement with BIPMs recommended values for the realization of the metre in the mise en pratique.

The results from the calibration are:

• Measured vacuum wavelength
• Relative deviation from the specified vacuum wavelength
• Difference between longest and shortest measured wavelength
• Diagram showing the relative deviation of the vacuum wavelength from specified vacuum wavelength

Finally, a system check of the object is performed against one of our own interferometers along a distance of 3 m  

Deliveries

The calibration results are reported in a digital calibration certificate in Swedish or English which states that the calibration was performed at a national laboratory.