After the war, new needs arose to produce some of the receivers and light sources used by the Company. These developments quickly made new premises necessary which led to the creation of a vacuum laboratory.
The entire usable area on the Arcueil site was built in 1949. It had become clear by 1954 that, even taking into account the possibility of partial elevation (which was actually carried out in 1957), the Arcueil plant would quickly become too small.
An 11,000 m2 plot of land was therefore acquired in Longjumeau in 1956 on which, in two stages, a new factory of about 5,000 m2 was built. The last phase of this construction was completed in April 1962.
The Longjumeau plant groups, with the exception of Optics, includes all of the actual manufacturing workshops - machining, adjustment, assembly, electronics, adjustment - as well as the manufacturing management, with its own administrative and technical departments.
It also houses vacuum laboratories, which produce certain types of photoelectric cells and special lamps.
Finally, it includes an underground room whose thermal insulation was specifically designed, in which the Company is conducting studies on the manufacture of diffraction gratings.
A large and pleasant company restaurant allows staff who work during the day to relax during their meal breaks.
Today, after several renovations, the Longjumeau plant is still operational and houses, in particular, the production of Scientific instruments, as well as those of the Automotive and Process and Environment departments.