Laser sources for interferometry

Project Description

The supply of He-Ne laser tubes suitable for use in green (543 nm) Zeeman stabilised lasers is now an issue as the main manufacturer has ceased production. These lasers are in use at many EURAMET NMIs, typically within the Gauge Block interferometers manufactured by Hexagon Metrology UK. In order to continue the manufacture of these lasers and to support future upgrades, replacements, repairs, a consortium of NMIs will collaborate and exchange information on several aspects of stabilised lasers for interferometer use. Tasks will include: exchange of information about laser components and their supplies; consorted campaign to persuade a laser manufacturer to manufacture tubes to a common design specification; work on novel stabilised laser designs (e.g. laser diodes).

Final Report 2020-10-13

The project concerned the ongoing supply of critical laser tubes used throughout length metrology both for the realisation of the metre, and for lower accuracy laser standards used in many dimensional metrology interferometric systems. A recent loss of a major supplier had caused issues of availability of tubes operating at 633 nm (especially those needed for iodine-stabilised lasers of the mise en pratique) and also 543 nm lasers used with gauge block interferometer.
An email survey of the needs for such laser tubes has been conducted resulting in a list of needs from several EURAMET members. Separately, we were informed that former employees of the close laser manufacturer have set up a new company (Pacific Lasertec: https://pacificlasertec.com/) and that they have re-started production of many types of laser tubes, including all of those listed in the survey (including an additional requirement for yellow laser tubes at 594 nm).
Several NMIs have since ordered laser tubes from this company and have found them to be suitable for their needs. At the TC-L 2020 meeting the coordinator asked if there were any un-answered needs from the TC-L members, and none were identified, so it was decided to close this project.