V-300-FIZ-300H is a Visible Vertical Interferometer by Armstrong Optical Ltd and partners, designed for convenience and ease of use for surface testing of optical flats and polished mounted/unmounted windows up to 300mm in diameter, and accepting Window Assembly or Fore Body structures of 350mm in height.
The design is the successful conclusion of drawing upon the experience and expertise of Armstrong Optical and partners, spanning and evolving over three decades during extensive hands-on experience of Visible and IR interferometry. This includes the practical measurement of wavefront aberration of thermal imaging lens and mirror systems, optical homogeneity of materials and flatness of optical surfaces. The instrument is configured to be user-friendly; all operations optimised for practical ease of use.
The V-300-FIZ-300H is an enclosed Fizeau interferometer utilising (a) an internal stabilised Class IIIb HeNe 633nm Laser System for wavefront measurement, (b) an internal Class IIIb 633nm Laser Diode for Sample alignment, (c) high-resolution visible camera, (d) a test chamber for handling, support, alignment and phase shifting of the Sample (including mounted windows, or optical flat), and (d) wavefront analysis software.
The internal stabilised Class IIIb HeNe 633nm Laser System with the collimating optics projects a collimated 305mm diameter Class 1M measurement beam down into the Test Chamber. Within the Test Chamber is a 300mm diameter tip/tilt stage incorporating high load phase-shifting capability. The tip/tilt stage is accessed via the large front door, which pulls out (along precision slides) to allow for loading, positioning and acceptance of the sample, and pushes back inside for the sample alignment and test position.
The Test Chamber accepts optical flats and windows up to 420mm in diameter, and mechanical structures of 420mm in diameter and 350mm in height for those mounted windows. The Ideal Test Analysis Zone (ITAZ) is 2mm to 40mm below the Transmission Flat; and to achieve ideal positioning for optical flats and unmounted windows an Airy Point Assembly (APA) is provided.
Coarse alignment of the Sample to V-300-FIZ-300H is achieved by engaging the 633nm Laser Diode Arm to create a reflective spot off both the Transmission Flat and the Sample Surface onto a diffused screen; adjustment of the tip/tilt stage brings the two spots coincidental.
The V-300-FIZ-300H utilises a 6MP visible camera; camera control and image displayed via a desktop computer and mShape™ wavefront analysis software provided by TRIOPTICS. Though the system focus and zoom are set are set to the ITAZ, the software provides a digital zoom capability.
