Iodine frequency-stabilized HeNe laser amplified by injection locking of a semiconductor laser diode

Abstract

The realisation of the meter definition is still today mostly performed using iodine frequency-stabilized HeNe lasers. Unfortunately, they deliver little optical power. Instead of migrating to other expensive laser technologies, the use of an injection locked semiconductor laser is proposed in order to boost the optical output of the legacy HeNe laser primary reference. The characterisation of the system and its validation through a comparison measurement is reported whereby no impact on the frequency and the stability of the HeNe reference laser could be observed.

Editorial for the Metrologia Focus Issue on Length Metrology

“…These traceability chains underpin an enormous breadth of calibrations and artefact standards for dimensional metrology that still rely on primary-level interferometric calibration, with the lowest level of uncertainty, at the NMIs and DIs. This results in ongoing work in both selecting [5] and developing light sources for these interferometers [6] as well as developing new forms of interferometers. These include double-ended interferometers which measure in two directions simultaneously in order to avoid issues associated with mechanical contact of surfaces [7,8].…”

“…The need to deliver NMI-level angle metrology in an industrial/research setting was foreseen in the 2018 CCL Strategy Document [21] which saw the need to realise the SI units in situ, where the highest accuracies are required. Other technologies such as secondary standards based on silicon [17] or more powerful stabilised lasers [6] can play a part here, especially if the needs of nanotechnology and nano-scale manufacturing continue to follow the predictions of Taniguchi [22]. Eventually, the secondary realisation of the metre may no longer be sufficiently precise (see figure 1).…”