Other Fizeau 

   Grazing Incidence

   How Phase Works


   Other Graham 


   Model 6VPS

   Model 8VPS



This 4-inch aperture vertical Phase Interferometer, as shown, is configured for Plano work only.  There is no requirement to purchase a separate transmission flat, -- the 1/20 wave reference surface is included and forms an integral part of the collimator. 

Note that if spherical work is planned, an optional Tip/Tilt plate with bayonet mount is required to attach external Transmission Flats or Transmission Spheres should be ordered at time of purchase.  In general, our Model 4HPS is recommended if both Plano and Spherical work are intended.

For Plano work the vertical format is often preferred, since there is no need to mount the test piece in a fixture.  The operator merely places it on the integral tip/tilt table and makes the appropriate adjustment. The overall height of the 4VPS is dependent upon the length of the vertical support rails chosen by the customer at the time of purchase.  The Model 4VPS incorporates a sturdy tip/tilt table which has been designed to support substantial mass. Its height is adjustable in order to suit the requirements of the operator.

A Two Spot alignment feature is accessible through the remote control which also controls Focus, Zoom and Intensity. The 4VPS is equipped with EndoPhazeTM phase shifting under the control of Durango Universal Interferometry Software and installed in a high speed computer equipped and includes a 22-inch TFT flat screen monitor.  Durango provides a wide selection of data outputs and colorful graphics and offers a live interferogram on the computer monitor.   No separate video monitor is required.

This rugged instrument is equally at home in the QC lab or in the optical fabrication shop. With excellent repeatability and reproducibility, this precision instrument provides the metrology required for all of your optical shop requirements.


4-inch aperture (101.6 mm) 1/20 wave reference surface is part of the interferometer
Proprietary Optics for superior performance Highest contrast and cleanest interferogram of any interferometer available today. No bull's-eye aliases!
Rugged construction High mechanical stability
A Turnkey System User Friendly and ready to go
Vertical rail structure Select 30, 36, 42, or 48 inch rails at time of purchase
Two spot alignment For quick setup on each new part tested
Single Mode Diode Laser source (635 nm) Dithered for Sharp, speckle-free images
Zoom Optics (4X) Readily accommodates test pieces from 1/4 inch to 4 inches diameter
Zoom, Focus, Iris, Intensity Controls Remote Control for quick adjustments
Sturdy adjustable height Tip/Tilt Table for heavy test pieces Accommodates large assemblies
EndoPhazeTM  Frrequency Shifter For smooth phase measurement with no hysteresis.
CCD Camera 768(H) x 494(V) pixels High resolution
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
2.2 GHz All-in-One computer  For high speed data reduction and small footprint
Live interferogram on computer monitor For quick inspection with no need for a video monitor
Tip/Tilt plate with bayonet mount to attach external Transmission Flat or Transmission Sphere Available as an option. 
Other 1/20 wave Transmission flats available 4% reflectance or higher as required
Interferometer can be removed from vertical rails for use in Horizontal format. Horizontal mode preferred for spherical measurements which require the addition of a transmission sphere.
 Repeatability 1/300 wave PV   1/1000 wave rms
Data Acquisition time 30 milliseconds (typical) Fast !
Data reduction time  ~3 seconds (typical) Fast !
Dimensions (H x W x D) 48 x 12.5 x 14 inches (typical) Small footprint
Weight 120 pounds (typical) Solidly built for high stability
Power 117 V 60 Hz 2 A (or 240 V 50 Hz 2A) Wired with plug to suit the user's power source
Manual Illustrated Operator's Manual
 2-YEAR WARRANTY New two-year limited warranty against defective components or workmanship

Graham Optical Systems,   9530 Topanga Canyon Blvd., Chatsworth,  California 91311
For Further Information today, call Gordon Graham today at (818) 700-1263   E-mail: 
Copyright © 2014 Graham Optical Systems  All Rights Reserved 
EndoPhazeTM is a trademark of Graham Optical Systems      *Durango is a trademark of Diffraction International
This page last updated February 21, 2014