4-inch Aperture Fizeau Interferometer 
Operates at 3392 nm and 635 nm

  Other Dual Wavelength

  Infrared Interferometers

  Fizeau Interferometers

  Grazing Incidence

  Why Grazing Incidence?

  How Phase Works

  Advantages of Dual 
  Wavelength Interferometers


  Printable PDF File


The 4-inch aperture Model 339irVIS interferometer operates in two modes: Infrared or Visible -- selectable with a switch. The instrument features a Zinc Selenide collimator and reference surface which is flat to 1/20 wave (measured at 632.8 nM). Two separate sources are employed -- a Helium-Neon Laser operating at 3392 nm and  a single mode diode laser operating at 635 nm.  At both wavelengths, speckle-free live interferograms are shown on the computer monitor.

The Model 339irVIS is quipped with two Cameras: a broadband Infrared camera and a standard CCD camera with 768 x 494 resolution for the 635 nm mode.  Two options are offered for the Infrared camera: Low Resolution at 320x256 pixels, and High Resolution at 640x512 pixels. This phase-shifting Fizeau interferometer utilizes piezo-electric phase shifters and Durango Universal Interferometry Software to permit the operator to achieve highly accurate and repeatable measurements at both infrared and visible wavelengths.

In typical usage of a Dual Wavelength Interferometer, the operator can align his optical system and perform any necessary tip/tilt operations with the interferometer in VISIBLE MODE -- greatly simplifying the procedure. 


While in the VISIBLE MODE, surface flatness measurements may be made at the higher accuracy 635 nm wavelength. The interferometer can then be put into the fully aligned IR MODE with the simple flip of a switch  These interferometers are provided complete with Durango Universal Interferometry Software installed in a fully configured 2.2 GHz Computer with an Intel Dual Core processor and includes a 22-inch TFT flat screen monitor..

Dual Wavelength 3392 nm / 635 nm Alignment of two wavelength optical paths is coaxial
4-inch aperture  Ideal for test pieces from 1/2 to 4 inch diameter
Zinc Selenide Collimator / Reference Surface  1/100 wave at 3392 nM, 1/20 wave at 635 nm
Infrared Mode Camera Lens (3392 nm)  100 mm F/1.0 Zinc Selenide Lens with iris
Visible Mode Camera Lens (635 nm) 4x Zoom 
Configuration Fizeau Plano Configurations
Dithered Illumination High contrast, speckle-free interferograms
Zoom, Focus, Iris, and Intensity remote controlled For optimum performance
Two Infrared Camera Options  320x256 pixels or 640x512 pixels
Alignment Mode Two Spot Alignment for both Infrared and Visible Wavelengths
Visible camera resolution 768 x 494 pixels
Piezo-electric Phase Shifter under control of Durango Software ~ 8 fringes of phase shift at 3392 nm
> 20 fringes at 635 nm
Live interferogram Either infrared or visible interferogram computer monitor
Accuracy (uncalibrated) 1/100 wave at 3392 nM, 
1/20 wave at 632.8 nM
Accuracy (calibrated) 1/250 wave at  3392 nM,
1/100  wave at 632.8 nM
Repeatability  1/300  wave PV, 1/1000 wave rms
Infrared Laser 3392 nM wavelength  Internal 2.0 mW Laser
Visible Laser 635 nM wavelength  1.0 mW
Dimensions (L x W x H)   24 x 18 x 10 Small footprint
Weight approx. 110 pounds (50 kg) Solidly built for stability
Windows environment
PV and rms in users choice of units
High level of repeatability
Excellent reproducibility
Large choice of graphic displays
Dynamic Sections
3-D OPD Plot
Reference Subtraction
MTF and PSF graphics and plots
Zernike Polynomials available for all measurements
Seidel Coefficients available
3.02 GHz computer with INTEL® Core™ i-3 540 processor
Data acquisition time 30 milliseconds (typical)
Data reduction time ~3 seconds
22-inch TFT Flat screen monitor For easy viewing
Power 115 / 249 Volts 60 / 50 Hz Wired with proper plug for user's power system
Test Beam Height 5.25 inches (13.3 cm)
Warmup time  30 minutes

For Further Information,  call Gordon Graham today at (818) 700-1263 E-Mail:  techinfo@grahamoptical.com
Graham Optical Systems,   9530 Topanga Canyon Blvd.,   Chatsworth, CA 91311
Copyright © 2014 Graham Optical Systems  All Rights Reserved   ***Durango is a trademark of Diffraction International
This page last updated July 16, 2014