As the Danish National Metrology Institute, DFM offers accredited calibration of gauge blocks for length measurement equipment using various methods. The most accurate method is laser interferometry, whereby the length is derived from the interference patterns created by two lasers at different wavelengths.
Like many other metrology institutes, DFM has used a commercial Zeeman-stabilized 633 nm HeNe laser combined with a custom-made stabilized green HeNe laser at 543 nm. However, the latter laser is no longer commercially available, so DFM had to look for a replacement.
We decided to replace the 543 nm HeNe laser with the 771 nm output from our Stabiλaser 1542 product. The Stabiλaser 1542 provided us with several benefits like the following:
- Excellent long-term reliability due to the laser being a fiber laser. In contrast, HeNe lasers are based on gas tubes that must be exchanged and re-calibrated regularly.
- More robust measurements due to a cleaner interference pattern with the Stabilaser.
Overall, we were very happy with the shift to the new 771 nm laser line from the Stabilaser which is now an integrated part of our length calibration laboratory.