Instruments that measure light by interfering with it.
Est. 1911 · Rotterdam
Coldlight builds instruments that convert the wave behaviour of light into a number: interferometers, plate cameras, coherence analysers, atmospheric monitors. A 400 mm aperture flat leaves the shop holding its figure to λ/40 at 632.8 nanometres. Below that tolerance a fringe pattern stops describing the wavefront under test and starts describing the errors of the instrument reading it.
No polishing machine finishes that surface. Computer-controlled laps remove material evenly and leave subsurface damage that prints through once the coating goes on; a bench optician reads the live fringe and corrects it by hand, stroke by stroke, until the interferogram goes quiet. The archive’s contact plates are held flat to 2 µm across the holder, because a plate that bows loses fringe order at its edge before the emulsion is exposed. The annealed blanks Coldlight specifies drift 0.9 nm/K, so a lab that cannot hold its air to within a degree cannot hold its glass to within a fringe.
There is no coating, no algorithm and no clever mounting that stands in for a hand that stopped lapping at the correct stroke. An interferometer tells you what the wavefront is doing, or it tells you what the room is doing. It does not do both.
12 accreditations. The earliest granted in 1923, the most recent in 2011. Every one still active on instruments built this year.
- SINCE 1958ICR
Interlaboratory Calibration Register
Traceable to national length standard
- SINCE 1974OSC·II
Optical Standards Consortium
Class II surface figure accreditation
- SINCE 1981λ/40
Wavefront Conformity Board
Peak to valley across full aperture
- SINCE 1923GMR
Guild of Metrological Refiners
Master grade, continuous since admission
- SINCE 1996ATM-7
Atmospheric Instrument Panel
Sealed to 7 bar, salt fog qualified
- SINCE 1967OBS
Observatory Supply Directorate
Approved supplier, primary optics
- SINCE 2004D·9
Dispersion Test House
Nine-line spectral verification
- SINCE 1989VRT
Vertical Reference Assembly
Gravimetric alignment, 0.2 arcsec
- SINCE 2011ECL
Extreme Conditions Laboratory
Rated 218 K to 341 K without drift
- SINCE 1948HRT
Heritage Register of Trades
Protected workshop, hand-figured optics
- SINCE 1999CHR
Coherence Measurement Panel
Verified to 40 m coherence length
- SINCE 1986A·400
Aperture Certification Office
400 mm clear aperture, edge to edge
Four instruments in current production.
Facility readout.
Figures as logged this quarter, not projected.
- Years in operation
- 115
- Instruments in service
- 640
- Oldest under active calibration contract
- Delivered 1953
- Best wavefront error achieved
- λ/40
- Largest clear aperture handled
- 400 mm
Tell us the tolerance you need to hit.
Send drawings, a wavelength, or a deadline. The more constrained the problem, the closer the first quote lands.