Spectrum Lasers

Spectrum is a range of Frequency Stabilised Lasers offering the user the choice of different laser wavelengths. Users of specialised Interferometry will find Spectrum Lasers provide the variety and flexibility they need. Spectrum Lasers are a key element in the Primary level of Calibration afforded by the NPL-Hexagon Gauge Block and Length Bar Interferometers.



  • High frequency stability laser light sources 
  • Choice of  laser wavelengths: 
    • Red light emission (Zeeman stabilized)   
    • Yellow light emission 
    • Green light emission 
  • Designed by the UK National Physical Laboratory (NPL) 
  • All Lasers have calibration certificates of their frequency, supplied by NPL 
  • Versions can be supplied as: 
    • Full or Short Lasers (the Full has an Acousto-optic Isolator and a Fiber Launcher) 
    • Fiber Launcher for Multi-mode (MM) operation is standard 
    • Fiber Launcher for Single-mode (SM) operation can be supplied on request 
  • Hexagon offer a refurbishment service for all Spectrum Frequency Stabilised Lasers 

Spectrum Model

Nominal Wavelength
633 nm (Red)
594 nm (Yellow)
543 nm (Green)
Output Power
Adjusted to < 1 mW(set to need)
Tested for < 1 mW(typically > 0.2 mW SHORT & > 0.12 mW FULL)
SafetyClass (C)
2 (in operating state)
2 (in operating & set-up/service states)