Ä9|9MP Fizeau

Ä-Series Fizeau Interferometers

Ä9|9MP Fizeau interferometer

High Resolution with Low Spatial & Temporal Coherence

Ä9|9MP Fizeau interferometer enables practical Mid-Spatial Frequency measurement: Advanced camera limited optical design, controlled spatial and temporal coherence, and rapid data acquisition.

Low temporal and spatial coherence yields a sub-nanometer noise floor with 10's of picometer repeatability.

Temporal coherence control is accomplished using ÄPRE patented Spectrally Controlled Interferometry (SCI). In the short coherence mode interference fringes are isolated to the measurement surface. This eliminates interference fringes produced by other surface back reflections.

A spatial coherence buster minimizes speckles and spurious fringes, and other noise sources to minimize the measurement noise. Notably, the design achieves retrace error performance approaching 30 nm, even at maximum slopes of 1,200 fringes across the field of view

Advanced PSD Analysis and filtering reports the surface performance with easy to understand RMS result over a specified spatial frequency band.


  • Spatial Frequency Range: 0.2 l/mm to 120 l/mm
  • Fringe Solution: <1200 fr/aperture
  • Retrace Error* @ 1200 fringes: < λ/15*
  • RMS Simple Repeatability*: <0.03 nm RMS 2σ
  • Accuracy*: <0.15 nm RMS 2σ
  • Measurable Part Reflectivity: 0.5% to 40% Other options available