Zygo Verifire™ HDX Interferometer

The Zygo Verifire HDX interferometer includes all the great features of the popular Verifire HD – such as QPSI, and a long-life stabilised laser – and adds important enhancements like new best-in-class imaging and resolution for high instrument transfer function (ITF), superior characterisation of mid-spatial frequency content and high-slope surface deviations, as well as ZYGO's DynaPhase® dynamic acquisition technique that eliminates problems due to vibration and enables precision metrology in nearly any environment. 

Designed for Optimal Resolution and Performance
The Verifire HDX system has an all-new optical design that was rigorously engineered to support pixel-limited performance for its 3.4k x 3.4k (11.6 megapixel) sensor, delivering enhanced imaging which reveals surface features that have been difficult to discern with lower resolution interferometers. This ultrahigh spatial resolution doesn't come at the expense of speed. The system operates at a frame rate of 96 Hz, at full resolution – up to 10X faster than other high resolution interferometers that can have limited capability due to noise entering the much slower measurement.

Power Spectral Density (PSD) and diffraction analysis tools round out the mid-spatial frequency characterisation capability of the Verifire HDX system, and dissect and report comprehensive surface characteristics through a simple and intuitive user interface. 

Superior Reference Optics And Accessories
UltraFlat™ and UltraSphere™ reference optics are certified at λ/40 PVr or better, and are manufactured with strict control of PSD signature to minimise mid-spatial frequency content. These high-precision reference optics are recommended for use with the Verifire HDX interferometer in order to realise full performance capability of the system. UltraFlat Transmission Flats are designed to meet this level of precision regardless of whether they are used in a vertical or horizontal orientation, which affords more flexibility in your test setup.

Mx™ Software
ZYGO's proprietary Mx™ analysis software offers a wide range of operational features and a comprehensive data analysis suite including Zernike, slopes, PSD/MTF/PSF, prism angle, corner cube, and many more. This full-featured instrument control, data acquisition, and analysis software package has the tools for integrating with manufacturing processes, running automation, and reporting critical mid-spatial frequency characteristics. It has a simple and intuitive interface for efficient operation and easy learning curve. It also includes Python-based scripting and remote access for maximum flexibility and integration into complex test setups. 

Instrument Transfer Function – What it is, and Why it's Important
Optical surfaces have been specified for form error for many years, but as demands on optical system performance increase, so too does the importance of controlling mid-spatial frequency (MSF) characteristics. Tight control of MSF characteristics is needed to reduce light scattering and improve optical efficiency for extreme performance applications.

Small-tool deterministic polishing techniques, which are extremely efficient in correcting form error, can also impart unwanted mid-spatial frequency content onto an optical surface. Depending on the frequency and slope of the surface characteristics, traditional interferometer systems – which are well-suited for measuring surface form – are unable measure and quantify higher-frequency surface characteristics due to limited resolution. The lack of resolution means that higher frequency details are attenuated (see image at right), and may not show up at all in the measurement results.

This is where Instrument Transfer Function (ITF) comes in. An interferometer system will attenuate surface information based on its design (optical design, camera, wavelength), which determines its ITF... its ability to measure spatial frequency content of an optical surface. The Verifire HDX system, with its high-resolution 3.4k x 3.4k sensor and optimised optical design, has a higher ITF than any commercially available interferometer system, making it an invaluable tool for reliably measuring and quantifying mid-spatial frequency characteristics of optical surfaces. This provides optical designers with the ability to confidently specify optical surfaces to a higher degree of precision, and define ITF testing requirements to meet system performance goals.