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Application Notes

This page provides a list of all available Application Notes, grouped by type of product. All Application Notes are provided as PDF documents.

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Surface Profiling

Measuring with an Optical Diverter on a NewView
The Optical Diverter accessory makes it possible to obtain measurement data from surfaces not accessible to a standard optical profiler objective. The Optical Diverter combines a long working distance objective with a probe that has a small mirror at its tip. The mirror redirects the measurement beam at a 90° angle, making it possible to measure vertical or internal surfaces, such as the walls of a cylinder bore. Additionally, the Diverter can be used with the software's stitching feature so as to obtain a surface map of a larger area of the surface than could be attained with a single measurement, without compromising lateral or vertical resolution.   Get AppNote (PDF)
Diesel Fuel Injector Metrology
Today's Common Rail Diesel (CRD) systems require very high fuel pressures, requiring fuel injector sealing surfaces to be extremely flat and smooth. Stylus-based metrology systems may score the sealing surface, resulting in a leak path for the fuel under pressure. Precision sealing surfaces such as these can be measured and analyzed quickly, repeatably, and safely with ZYGO's Nexview non-contact optical profiler.   Get AppNote (PDF)
Cutting Tool Metrology
Modern manufacturing methods require the use of highspeed, multi-geometry, cutting tools for quick and efficient material removal. Cutting tools can require cutting edge honing, flute roughness inspection, and inspection for edge fracturing. Coherence Scanning Interferometry (CSI) techniques, used in ZYGO optical profilers, allow tool makers and users unprecedented access to the quantification of cutting tool surface parameters.   Get AppNote (PDF)
Optical Profiling of Highly-Sloped Surfaces
Measuring the form of highly-sloped surfaces has traditionally been a challenging application for optical profilers using Coherence Scanning Interferometry (CSI). Examples of these surfaces include optical micro-lenses, brightness-enhancing structures, and machined cones. Advances in signal detection and processing available on ZYGO's CSI-based profilers running Mx™ software vastly improve the ability to obtain valid topography data from surfaces with high slopes.   Get AppNote (PDF)
MetroPro® Films Analysis
The Films Analysis Application for MetroPro combined with ZYGO's flagship profiler, the NewView 6300, is the fastest and most versatile tool available for quantification and visualization of film surface and thickness characteristics. ZYGO's patented TopSlice and FilmSlice algorithms allow for the widest range of film thicknesses and unparalleled repeatability for total confidence in your film metrology.   Get AppNote (PDF)
Measuring Sub-Angstrom Surface Texture
The application of measuring surface texture with a white light optical profiler has been well-known for many years. As the capabilities of optical manufacturing and precision machining increase, the production of 'super smooth' or 'sub-angstrom' surfaces has become more common, and quantification of these surfaces is critical for effective process control.   Get AppNote (PDF)
Measuring Dynamic MEMS Devices
Dynamic measurement of a MEMS device is useful for both research and development and production quality control. Sweeping of device drive frequencies and illumination phase delays can be used by the researcher to validate design parameters and examine device resonances. As a quality check, dynamic measurement mimics the MEMS actual usage for a true functional test. Rapid characterization over the full range of motion and frequencies experienced is possible.   Get AppNote (PDF)
Identifying and Controlling Vibration
For the best measurement performance on the NewView™ 6000, environmental vibrations must be minimized. These vibrations can be transmitted to the instrument itself, the test part or in both. ZYGO's MetroPro™ software is supplied with simple and useful tools for quantifying vibration. With these tools and some common sense troubleshooting approaches, it is possible to identify sources of vibration and isolate them to produce the 'quietest' measurement environment possible.   Get AppNote (PDF)
MetroPro® PSD Analysis
In many industries, a powerful method of quantifying surface texture on smooth surfaces is Power Spectral Density (PSD) analysis. This method uses Fourier analysis to convert the spatial domain measurement data of a surface into its frequency components. Spectral analysis of this type is extremely useful in describing how a polished surface will scatter incident radiation - a critical performance metric in optical, semiconductor, and precision machining applications. MetroPro software has built in tools for PSD analysis that are very simple to set up and use. For users in the precision optics industry, ISO 10110-8 compliant units are available.   Get AppNote (PDF)
Included Angle Measurements
The NewView™ product family is designed and very well suited for high accuracy surface metrology measurements such as roughness, waviness and step heights. For these types of measurements, accuracy in the vertical or Z direction is essential. The operation of interferometers is well understood and vertical information is very accurate.   Get AppNote (PDF)
Vision Software Suite
Simultaneously performing 2D image analysis and 3D measurements using the same data is one of the strengths of the NewView™ family of white light profilers. The Vision Software Suite (VSS) for MetroPro™ makes this process simple and straightforward by adding the power of Cognex VisionPro to the surface characterization capabilities of ZYGO's MetroPro.   Get AppNote (PDF)
ABS Geometry and MetroPro® Calculations
This technical note describes the analytic calculation of ABS geometry as done by MetroPro with particular emphasis on the differences between cylindrical and spherical head geometries.   Get AppNote (PDF)
Getting the Most from the Advanced Texture Application
The Advanced Texture application is designed to filter roughness information from data that contains a combination of waviness, roughness, and high frequency noise. This application may be necessary for a variety of reasons, including: part form is too complex to be removed using 'cylinder' removal in Micro.app, or measurement noise cannot be avoided using regular measurement controls The Advanced Texture FFT filter frequencies are designed to do two things: The High Frequency filter is used to filter out noise. The Low Frequency filter is used to filter out overall part waviness (and complex form).   Get AppNote (PDF)
Filtering on the NewView™
Data obtained with the NewView is a model of the surface under test, not an exact duplicate. It is "spatially bandwidth limited" due to fundamental physical limitations and inherent measurement inaccuracies. In other words, the features of the true surface have been low-pass filtered and information on the very high spatial frequencies is lost in the measurement process. The extent of this filtering is determined by instrument design, system configuration, and physical principles.   Get AppNote (PDF)
PV versus RMS
Peak-to-Valley error (PV) is a worst case error statistic. Calculation of the PV error uses only the high and low point on the surface relative to the reference surface. Since this only compares two points on the surface, it is possible for two very different surfaces to have the same PV error. The PV error does have the advantage that it is very easily estimated visually from the interferogram. It has the disadvantage that one small dig, or other artifact in the surface, can cause the PV to be very large even though the optic may perform quite well.   Get AppNote (PDF)
Photovoltaic Panel Measurement on a NewView™
For photovoltaic panels, there is an increased need for manufacturers and researchers to inspect features such as line width and height, cross sectional area, and surface roughness, on these types of samples. ZYGO's MetroPro™ software includes comprehensive photovoltaic analysis. When used with its Vision Software Suite, it simultaneously performs 2D and 3D surface measurements of a wide variety of solar cells and similar photovoltaic devices.   Get AppNote (PDF)
Measuring Honed Surfaces with a NewView
Machined surfaces which undergo the honing process are often measured for honing angle, surface roughness, and bearing ratio. In the case of cylinder bores, characterization of these parameters provides valuable information on expected wear, life span, oil retention, and oil consumption. The NewView optical profiler provides fast, non-contact measurement of honed surfaces, including cylinder bores, with the added benefit that it is not necessary to cut the part in order to measure the internal surfaces. With the MetroPro CrossHatch application, it is possible in a single measurement to acquire a rich set of results, in both numeric and graphic formats. This data can be used to evaluate the relative strength of a surface which has distinct lay direction.   Get AppNote (PDF)

Laser Interferometry

Metrology in Production Environments
QPSI technology is an easy to use vibration-robust acquisition solution that maintains the accuracy of a true-Fizeau interferometer. Combined with a complementary hardware configuration, the patented QPSI algorithm quantifies the rigid body motion of the measurement cavity and compensates for the vibration in each subsequent acquisition, thus eliminating the fringe ripple that may occur in a PSI measurement.   Get AppNote (PDF)
Coherent Artifact Reduction System (CARS)
Artifacts in interferometric data, such as the "bulls-eye" typically caused by surface dust in the coherent beam path, can print through on the height map, affecting the magnitude and repeatability of the surface measurement. An extended source solution works primarily with phase-shifting metrology. ZYGO's Coherent Artifact Reduction System (CARS) is designed specifically to work with dynamic acquisition while still significantly reducing the noise in the data and removing artifacts, allowing more surface features to be resolved.   Get AppNote (PDF)
DynaPhase™ Set-Up Guide
This document details nine basic measurements setups for the DynaFiz™ interferometer system when using the DynaPhase™ acquisition mode. A DynaFiz™ interferometer with a PMR can also measure in PSI mode, in which case the ZYGO's Guide to Typical Interferometer Setups can be used instead of this guide.   Get AppNote (PDF)
Grazing Incidence Testing
When performing interferometric measurements on rough, non-specular surfaces such as unfinished metal or ceramic, it can often be difficult to obtain a sharp fringe pattern or any fringe pattern at all. This occurs because light from the interferometer is absorbed or scattered by the test part. This affects the returning wavefront and subsequently the resulting fringe pattern. This situation can be avoided by using a test method known as Grazing Incidence Testing.   Get AppNote (PDF)
Interferogram Scale Factor
The geometrical properties of an interference fringe pattern are determined by the difference in optical path traveled by the recombining wavefronts. However, there is no indication as to whether this wavefront has traveled through a window, reflected from a surface, or at what angle it has reflected from a surface, etc. The Interferogram Scale Factor (ISF) specifies how this input wavefront error is scaled to properly represent the output parameters which the user wants to display in the results.   Get AppNote (PDF)
Testing Cylindrical Surfaces with Computer Generated Holograms
Testing cylindrical surfaces using a conventional interferometer requires generating a cylindrical wavefront to match the curvature of the surface. A computer generated hologram (CGH) may be used to generate such a wavefront. This document describes the use of a CGH designed for cylinder surface testing, in conjunction with a ZYGO interferometer and MetroPro software.   Get AppNote (PDF)
Fringe Analysis versus Phase Measuring Interferometry
Interference patterns may be analyzed a number of different ways. The two most common are fringe analysis, and phase measuring Interferometry. Fundamental differences between these two methods meand differences should be expected in the calculated results, such as PV(peak-to-valley) or RMS (root mean square). Careful operator technique should minimize the differences, but some differences are due to the nature of the part under test and the interferometer itself. This App Note explains the analytical and practical difference between fringe analysis and phase-shifting interferometry.   Get AppNote (PDF)
Finite Conjugate Lens Testing
This App Note outlines a procedure for testing a conjugate lens using a ZYGO interferometer and MetroPro software.   Get AppNote (PDF)
Testing Cylindrical Optics
This App Note describes and evaluates strategies for testing cylindrical components, using a ZYGO interferometer with standard ZYGO interferometer accessories. The analysis and discussion are directed towards measurement of surface irregularity of concave mirrors and wavefront irregularity or positive lenses. Test geometry, data interpretation, alignment and analysis are discussed in each case. Test setups are illustrated, software usage is discussed, and comments are made on the induced aberrations and the interpretation of the interference data.   Get AppNote (PDF)
MetroPro® Cylinder Tools
ZYGO's MetroPro® software provides controls and results which allow analysis of interference patterns from cylindrical surfaces and cylinder lenses. This App Note summarizes the MetroPro features and provides an introduction to their use.   Get AppNote (PDF)
Pentaprism Testing
This 8-page App Note provides a detailed overview of test setups and analysis for testing pentaprisms with a ZYGO interferometer system and MetroPro software.   Get AppNote (PDF)
Subtraction of Transmission Sphere Reference Data
This App Note describes how to use absolute testing data to reduce systematic measurement errors due to the quality of the Transmission Sphere reference surface.   Get AppNote (PDF)
Critical Alignment of Transmission Flats
For certain measurement applications, such as those those using a Dynaflect coated transmission flat, or when using Ring Mode on a Verifire AT, a more precise alignment of the transmission flat is required than can be achieved using the alignment reticle only. This App Note describes how to use a retroreflector for precise alignment.   Get AppNote (PDF)
Critical Alignment of Transmission Spheres
For certain measurement applications, a more precise alignment of the transmission sphere is needed than can be achieved using the alignment reticle only. Some of these applications include: absolute testing for spheres with PV <λ/50 using high f/no. transmission spheres, absolute testing for spheres with PV <λ/20 using the lowest f/no. transmission spheres, and setups in which slight misalignment of the transmission sphere may introduce unwanted fringe patterns or artifacts. This App Note describes how to use reflection from a surface in cat's-eye position for precise alignment of transmission spheres.   Get AppNote (PDF)
Using Static Fringe Data in PHom.app
The Polished Homogeneity Application (PHom.app) was developed to acquire data on phase shifting instruments. However, it is possible to load static fringe data into the application and successfully calculate results. Care must be taken when acquiring and analyzing the data, and this Tech Note provides guidelines for making measurements correctly as well as suggestions for improving the accuracy of the PHom results.   Get AppNote (PDF)
Imaging at the Cats-Eye Position in the Two-Sphere Test
When making absolute measurements using the two-sphere test, two types of measurements are required. One is a series of confocal measurements, in which the surface under test is concentric to the reference surface of the transmission sphere being used. The other is a cats-eye measurement, in which a reflecting surface is placed at the focal point of the light from the transmission sphere and perpendicular to the optical axis of the system. This App Note explains the measurement technique.   Get AppNote (PDF)
Critical Alignment of Aperture Converters
When using an aperture converter for beam expansion or compression, one must make certain that the optical axis of the aperture converter is well aligned to the optical axis of the interferometer. Misalignment induces non-symmetric aberrations in the transmitted wavefront exiting the aperture converter, which results in ray-tracing error that increases measurement uncertainty. To minimize measurement uncertainty, a more accurate alignment of the aperture converter to the optical axis of the interferometer can be achieved by substitution of a retroreflector in place of the interferometer alignment reticle.   Get AppNote (PDF)
PV versus RMS
Peak-to-Valley error (PV) is a worst case error statistic. Calculation of the PV error uses only the high and low point on the surface relative to the reference surface. Since this only compares two points on the surface, it is possible for two very different surfaces to have the same PV error. The PV error does have the advantage that it is very easily estimated visually from the interferogram. It has the disadvantage that one small dig, or other artifact in the surface, can cause the PV to be very large even though the optic may perform quite well.   Get AppNote (PDF)
RMS Multipliers for Seidel Coefficients
This App Note describes how to convert Seidel coefficients to those representing the RMS aberration, using ZYGO MetroPro software.   Get AppNote (PDF)
PVr - A Robust Amplitude Parameter
It is a well-established practice in optics manufacturing to specify optical surfaces based on the peak-to-valley(PV) departure from nominal surface shape. However, it can be biased by noise, often producing a result that is not representative of actual surface form. PVr is a robust and repeatable amplitude specification for optical surfaces, simplifies specification of mainstream optical surfaces, and can reduce disagreements about surface characterizations made on different instruments.   Get AppNote (PDF)
Ultrasphere Transmission Spheres; Zernike Correction at 1X Zoom
The Ultrasphere™ TS (transmission sphere) products include absolute calibration of the reference surface, and the resulting three files are shipped on a USB flash drive with the TS. This procedure in this App Note ensures increased accuracy by removing the low-order Zernike error from the reference surface. It should be done each time an Ultrasphere TS is re-installed on the interferometer.   Get AppNote (PDF)
Understanding the PV Specification
An array of non-standard, arbitrary practices are frequently used in the optics industry to demonstrate conformance of a part to the traditional peak-to-valley (PV) specification. Some of these practices include filtering, trimming, masking, and spike removal. These techniques can be time consuming and the result lacks consistency between instruments and operators. PVr is a new measurement result that significantly reduces the large variations that often occur when using PV.   Get AppNote (PDF)
Silver Overcoat Spray
This App Note provides a source for optical-quality high-reflective silver overcoat spray used for testing optics with rough surfaces. Some optical manufacturers have applications requiring the rapid deposition of this coating on a surface, which can then be stripped after the surface is measured.   Get AppNote (PDF)
Certifiable Full Area Calibration of Plano Reference Optics
ZYGO has developed a full-area calibration technique that is an extension of the traditional 3-flat test, and can be used for certifying reference optics up to 32-inches in diameter. Similar to the 3-flat test, a set of 3 flats is required: 2 transmission flats and one reference flat. It is now possible to achieve a higher level of performance while providing more margin in the manufacturing of production optics.   Get AppNote (PDF)
Guidelines for Using the ISO 10110-5 Application with the Mini™ XP
The Mini XP is a compact, self-contained, metrology system designed for production situations. Several data analysis packages make it possible to easily quantify critical form metrology parameters of optical surfaces. The ISO 10110-5 Application directly reports ISO-compliant results scaled to the proper wavelength and comparative radius of curvature testing. There are distinct differences in the way the analysis in the ISO 10110-5 Application and Mini XP Advanced Application handles aperture and masking functions. This Application Note describes the use cases and differences.   Get AppNote (PDF)
Enhanced Performance with GPI™ CAN Upgrade
  Get AppNote (PDF)
Measurement of Aspheric Surfaces
Fizeau interferometers are easily configured to measure the surface figure of a wide variety of spherical surfaces. However, for an axially-symmetric asphere, it is not possible to match the entire surface to one reference wavefront because the curvature varies continuously across the part. ZYGO's Verifire™ Asphere system provides fast, flexible and high resolution 3D surface data for axially-symmetric aspheric surfaces, with measurement uncertainties as low as λ/10.   Get AppNote (PDF)
Determining Asphere Measurability
Several factors must be considered in order to determine the best measurement setup for a given asphere. To assist in determining the measurability of a specific asphere, ZYGO's calculator spreadsheet provides guidelines on the measurability of an asphere based on its equation, properties of available transmission spheres, and other optical and mechanical properties of the Verifire™ Asphere system.   Get AppNote (PDF)
Using the Auto Focus Feature with Non-ZYGO Transmission Spheres
The Verifire™ Asphere system (VFA) includes an auto focus routine designed for use with ZYGO transmission spheres. However, it is possible to use non-ZYGO transmission spheres for measurement of aspheric test parts on the VFA system and enable auto-focus functionality with manual entry of a few key parameters.   Get AppNote (PDF)

Asphere Metrology

Measurement of Aspheric Surfaces
Fizeau interferometers are easily configured to measure the surface figure of a wide variety of spherical surfaces. However, for an axially-symmetric asphere, it is not possible to match the entire surface to one reference wavefront because the curvature varies continuously across the part. ZYGO's Verifire™ Asphere system provides fast, flexible and high resolution 3D surface data for axially-symmetric aspheric surfaces, with measurement uncertainties as low as λ/10.   Get AppNote (PDF)
Determining Asphere Measurability
Several factors must be considered in order to determine the best measurement setup for a given asphere. To assist in determining the measurability of a specific asphere, ZYGO's calculator spreadsheet provides guidelines on the measurability of an asphere based on its equation, properties of available transmission spheres, and other optical and mechanical properties of the Verifire™ Asphere system.   Get AppNote (PDF)
Using the Auto Focus Feature with Non-ZYGO Transmission Spheres
The Verifire™ Asphere system (VFA) includes an auto focus routine designed for use with ZYGO transmission spheres. However, it is possible to use non-ZYGO transmission spheres for measurement of aspheric test parts on the VFA system and enable auto-focus functionality with manual entry of a few key parameters.   Get AppNote (PDF)

General Information

Mx™ Non-Instrument Installation Procedure
Mx™ software may be installed on computers that are not connected to a profiler or laser interferometer, for off-line analysis of captured data. This document explains how to download and install Mx software on desktop and laptop computers that meet hardware and operating system requirements.   Get AppNote (PDF)

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