This laser represents an optical frequency standard with a relative uncertainty of 2.5 x 10 -13 [1] that can be used to realize the SI unit of length, the meter with highest accuracy[2].
(This laser; represents; an optical frequency standard) (a relative uncertainty of 2.5 x 10 -13; can be used; to realize the SI unit of length)
This laser a relative uncertainty of 2.5 x 10 -13
represents can be used
an optical frequency standard
to realize the SI unit of length