• Unmatched absolute accuracy down to 2 MHz
  • Measurement ranges from UV to IR (192 nm .. 11 µm)
  • For pulsed and cw lasers
  • Sensitivity down to nW light power
  • Up to 600 Hz acquisition speed


The wavelength meters of the WS series accomplish wavelength measurements with highest accuracy. Both cw and pulsed lasers with narrow-band emission can be examined, monitored and even actively controlled. Various models of the WS series are available, covering UV to IR wavelength ranges (192 nm - 11 µm).  Based on a rugged Fizeau interferometer setup without any moving components, the wavelength meters provide quasi unlimited lifetime.

The spectrum analyzers LSA and HDSA allow for multi-line or broadband spectrum of light sources like cw and pulsed lasers, gas discharge lamps, super luminescence diodes, semiconductor laser diodes and LEDs.

Technical Information

Absolute accuracy of wavelength meter versions
Standard 350 - 1120 nm
UV 248 - 1100 nm
UV-II 192 - 800 nm
UV-II-VIS 192 - 1190 nm
VIS- IR 400 - 1750 nm
IR 800 - 1750 nm
IR-II 1000 - 2250 nm
  IR - III  2 - 11µm
192 - 370 nm [pm] 6 3 0.6 0.4 0.2 0.1 0.1 0.1
370 - 1100 nm [MHz] 6000 3000 600 200 60 30 101) 22)
1100 - 2250 nm [MHz] 12000 2000 400 150 40 20 101)
  2 - 11µm [MHz] 1-5nm3) 2000 200
Calibration Built-in4) Built-in4) Built-in Built-in4) Built-in External External External

1) ± 200 nm around calibration wavelength
2) ± 2 nm around calibration wavelength
3) depending on device type
4) except IR-III


Operation principle


HighFinesse Fizeau interferometer setup of WS series

Contrary to Michelson interferometer based instruments, our wavelength meter uses fixed Fizeau interferometers to detect the wavelength of a laser beam.

The beam enters the optical unit via a fiber, is collimated by a lens and then split into several beams. Each beam passes a Fizeau interferometer of specific length to generate distinct interferometric patterns. All these patterns are recorded by a CCD array and digitally transferred via USB interface to the operator’s PC. The firmware finally analyses the data and calculates the laser wavelength, taking into account the ambient temperature.

Due to the Fizeau interferometer setup, pulsed lasers can be measured at high measurement rate. The rugged setup also enables usage under extreme conditions (e.g. in airplanes with significant vibration).

Options & Related Products

MultiChannel - Simultaneous measurement of 2, 4, or 8 lasers
PID control - Locks your laser to any wavelength or tunes it along arbitrary functions. Can be combined with MultiChannel option
Linewidth option - Calculates the laser linewidth using the interferogram data
Diffraction grating - For spectral analysis of broad linewidth lasers
TTL - For synchronization of experiment and measurement

Please follow the  to learn more about the large variety of options!