for performance testing of infra-red materials and optical ii dual ir interferometer data...

NextGenn Global Technologies Limited

Infrared

Interferometers For Performance

testing of infra-red

materials and optical

systems

Specialist expertise in testing,

analysis, design, development and

manufacturing for Optical

fabrication, Optical Assemblies,

defense related engineering

disciplines including sensors, systems,

and electronics.

MANUFACTURING Solutions

A wealth of technical experience in

electrical, mechanical, electro-

mechanical and electro optical

systems is available for the assembly

and test of a variety of complex

subsystems. Production operations

and logistics expertise is

supplemented by project

management, manufacturing and

process engineering skills in order to

ensure cost effective delivery.

NextGenn Global Technologies Limited promotes a extensive range of specialist

testing, analytical, design, manufacturing, and evaluation facilities to a wide

market across the Optics, Optical Assemblies , Laser diagnostics , aerospace

and defence industries. NextGenn has several programmes in the industry and

offers unrivalled capability in key technologies We offers access to this wealth of

expertise on a commercial, contract basis through three major disciplines:

Testing, Imaging and Manufacturing Solutions.


INFRARED II Dual Waveband IR Interferometer

The INFRARED II dual waveband Twyman-Green unequal path Interferometer

available with a choice of lasers operating at LWIR 10.6 microns wavelength, in

the MWIR 3.39 micron wavelength range which allows fringes to be obtained

quickly and easily with excellent signal-to-noise. We offers two options for Co2

Laser: One option uses Co2 Laser with 12 tunable lines (10.3-10.8 microns), this

can be fixed at 10.6 micorns and Second Option uses Co2 Laser with 45 tunable

lines(9.1-10.9 microns) . The Base unit includes IR remote control and 633nm laser

alignment source. To make the system compact and easy to use both 3.39 um

laser and 10.6 um laser are fitted inside same housing along with interferometer

and also the alignment laser built in into the same housing which makes our

system versatile and unique.

INFRARED II dual waveband Twyman-Green interferometers have been

designed to be rugged, Vibration insensitive , easy-to-use instruments that can

be used for development, test, production, quality control or research

applications where vibrations are present and are fully supported with a

comprehensive range of optical and mechanical accessories and static and

phase-measuring fringe analysis software options for the accurate measurement

of wavefront aberration of thermal imaging lenses, optical homogeneity of infra

red materials and flatness of optical surfaces. Our Interferometer is a real-time,

high-speed, truly vibration-insensitive metrology instrument with shutter speeds as

fast as few msec ~ 3-5 msec , the system is ideally suited for shop/production

floors and other vibration or turbulent environments, we achieve vibration

insensitivity using Spatial Carrier Methods.


The construction of this system combined with a fast warm-up time means that

fringe images can be quickly and easily produced with no focus drift. All

instruments feature a focal plane array camera which is much more sensitive

than previous cameras and has significantly reduced noise, allowing high quality

images of fringes to be acquired quickly, easily and with no focus drift. When

used with phase shifting fringe analysis software, the acquisition of fringes is

much more reliable. The phase shifting technique used allows the highest

degree of precision and enables full use of standard accessories.

The INFRARED-II dual waveband system operates at both 3-5 micron band using

3.39 micron HeNe laser source and at 10.6 using a stabilised CO2 waveguide

laser source operating at 10.6 microns. Alternative lasers are available for

different wavelengths. Both 3.39 micron and 10.6 micron Lasers along with

alignment Laser is housed inside a single housing to make the system compact

and easy to use.


The INFRARED-II dual IR provides the greatest possible accuracy in the measurement using our advanced PC and μShape™ Fringe Analysis Software. As precision non-contact instruments, the INFRARED II Dual IR interferometers provide rapid and accurate measurement of wavefront distortion through IR systems and components. Their operating wavelengths allow for the evaluation of high specification IR lens assemblies, producing interference fringes that indicate the degree of aberrated performance. Their associated fringe analysis software enables detailed performance analysis of even the most complex of lenses. It features a focal plane array camera which is much more sensitive than previous cameras and has significantly reduced noise, allowing high quality images of fringes to be acquired quickly, easily and with no focus drift. When used with phase shifting fringe analysis software, the acquisition of fringes is much more reliable. The Image Sampling of a focal plane array camera is

≥ 320 x 240 pixels for both the wavelengths 3.39 um and 10.6 um. This technical excellence of the system allows optical design services, optical testing, diamond machining and sub-assembly manufacturing. Each instrument comes with a comprehensive operating manual and is backed by a one year guarantee plus a choice of technical field service and support packages. The INFRARED II Dual IR interferometer systems is configured in a Twyman Green optical configuration and have an integral co-linear visible HeNe laser at 3.39 micron and a stabilised CO2 waveguide laser source operating at 10.6 microns included that provides the user with a rapid and accurate alignment system and are designed to provide versatile testing capabilities. KEY BENEFITS of INFRARED II Dual IR Interferometer: ■ Portable and compact ■ Easy to set up and operate ■ Provide remote control operation ■ Non-contact and precise ■ Transmitted wavefront measurement for IR materials/systems ■ Compatible with a wide range of standard accessories ■ Practical, versatile and affordable Advantages of dual wave band IR Interferometer’

■CONVENIENCE. Probably the most important advantage is the convenience of

making measurements in the infrared with the same interferometer -- WITHOUT

THE NEED TO REALIGN the test piece! This saves a lot of setup time. It also makes

it possible to do the basic alignment with the visible beam --often a great deal

easier when you can see the beam -- then switching to the ir beam after the

cantering and tip/tilting is done.


■ DYNAMIC RANGE EXTENSION. Accurate measurement of a surface with

greater departure from flat (or spherical) may be difficult when the wavelength

of the test beam is relatively short (632.8 nM). It may not be easy to get good

repeatable data when the departure exceeds 40 fringes. This is a case where

the longer wavelength of the infrared can be put to good use to reduce the

number of fringes substantially.

■ SPACE SAVING. Of course such infrared interferograms could be made with

two separate interferometers. Aside from the additional setup time -- a lot more

real estate must be devoted to two separate interferometers.■ COST. While

dual-wavelength interferometers are more expensive than single wavelength

instruments, the cost is less than for two separate instruments -- as much as 22.5%

less for some Models, but the ongoing, day-to-day savings in time spent aligning test pieces greatly overshadows any capital cost saving. Specifications:

Configuration INFRARED II Dual IR Interferometer

Description Dual waveband Twyman-Green Unequal Path

Interferometer

Acquisition Mode Temporal & vibration insensitive mode

Alignment Mode Integral co-linear visible HeNe laser

Wavelengths 3.39 um & 10.6 microns (others available)

Maximum Output Test Lasers : <4mW at MWIR waveband and <400mW at LWIR waveband both housed in single housing along with Alignment Laser: < 45 mW at 633 nm

Clear Aperture 15 mm (Expandable with accessories)

Maximum Cavity Length

>30 m

Polarization Linear

Pupil Focus Range +/- 10 mm (higher focus ranges are available as custom

made)

Pupil Magnification 1X to 3X

Camera High Resolution dual waveband 320x240 uncooled ferroelectric focal plane array

Motorized Controls System wavelength, Zoom, Focus, Tip-Tilt Reference Mirror

Additional Option Beam Attenuation(manual) for low reflectivity test surfaces

Computer System Minimum Dual Core 2 GHz processor, 4GB RAM, 320GB Hard drive, CDRW, DVDRW, 21 in LCD monitor, keyboard, mouse, frame grabber


Operating System Windows-7

System Software

μShape and FastFringe

μShape Phase Shifting data acquisition

FastFringe™ instantaneous data acquisition, storage and

export

Fringe contrast controlled via camera and frame grabber

settings

Reference generation, subtraction, data averaging,

masking, filtering, terms removal, multiple aperture analysis,

arithmetic

2D and 3D surface maps

Zernike / Seidel / Slope / Geometric / Fourier Analysis

Absolute sphere, aspheric analysis, prism & corner cube

analysis, multiple aperture analysis

Fringe detection Focal plane array with fringe contrast adjustments

Display CCIR compatible or as specific user requirements

System Performance Specifications: Analysis Parameters PV, RMS, Zerniker decomposition, slope, PSF, MTF,

Homogeneity

Accuracy (PV) wavefront<λ/50 P-V with reference calibration and

subtraction

Repeatability (PV) wavefront λ/100 P-V, λ /200 rms surface deviation λ/200 P-

V, λ/400 rms

Precision λ/1000 rms

Transmitted wavefront λ/4 PV or λ/20 rms

Acquisition Rate μShape™ 0.16secs to 1.33secs

FastFringe™ 20millisecs Dimensions 675mm (l) x 260mm (w) x 280 mm (h) Weight 35 kg approx

Power Consumption 720Watts Temperature Range Operational : 10–30°C, stability +/-2°C, non-condensing

Storage: 5–45°C, non-condensing


µShape Interferometry Software

μShape Interferometer Software was originally developed for the μPhase®

compact interferometers, today interferometers from other manufacturers work

with μShape™, too.

With its clear and menu driven user interface μShape perfectly deals with the

variety of measurement requirements and provides several modules which

expand the capabilities of μShape. The advanced level of the software is

demonstrated each time whenever the software is sold to support other

interferometers on the market.

In general, μShape works with all Windows® systems including Windows® 7 and is

designed for ease-of-use as well as full functionality. It controls and displays the

measurement results, stores and documents all measurement raw data and

ensures maximum transparency and traceability.

μShape Professional Software

The Professional version is the all-rounder amongst the μShape family. It is used for

measuring the topography of flat, spherical, cylindrical, toric and aspherical

surfaces or wavefronts and is employed in production, laboratory and research.

Add-on modules enable to adapt the software to custom specific demands.

These modules can be added at any time even after the purchase.

General Functions of the μShape™ Measuring and Analysis Software

Different levels with different access rights

Shortcuts for most used program functions

Comprehensive context-sensitive online help

Various program modes enable the separate visualization of calibration and

measuring processes and its parameters with an integrated live camera

image

Automatic updates of displays and images after every change of analysis

parameters and new measurement

Easily pre-configured templates for a wide range of measuring tasks and

analyses

Storage of all parameters and settings, including window size and position,

with specimen data in μShapeTM program file

Graphic windows can be stored in several graphic formats (bmp, jpg,..)

Export of individual parameters or of selected data fields as text, binary or

other common file formats (e.g. QED, Zygo XYZ, DigitalSurf) for external


processing

The measurement results are presented in parameters or graphically as a

cross section, in 2D or 3D

Printout of selected graphic displays or of the entire window

Measurement protocol shows the results at a glance and can be widely

configured including the customer`s logo

Access protection and configuration of add-on modules by dongle

Basic Measuring and Calibration Settings of μShape Software

Measuring parameters

Sets measuring parameters for any given measuring configuration: choice of

phase measurement method, phase computation, and phase-shift wait times,

separately for calibration and measurement of specimen.

Wavefront parameters

This function sets all parameters necessary for the computation of wavefronts,

such as subtraction of calibration data; activation of various smoothing and

holeclosing methods; compensation of adjustment errors for flat, spherical,

cylindrical, aspherical and toric specimen; and geometrical operations (rotation,

mirroring and data-field shift).

Masks

Sets geometrical elements (circles, ellipses, rectangles, squares and polygons) in

any combination as transparent or opaque masks

Configuration

Selects test setups, such as measurement of surfaces in perpendicular reflection,

wavefronts in double transmission, automatic conversion of results and scaling of

the measured field in units of length.

Visualization

Graphic display of data fields (intensity, phase image, measured data) displayed

as a cross-section, 2D or 3D image. All parameters and statistical values in table

form. Display of statistics, DIN and ISO parameters, Zernike and Seidel coefficients

is available.


μShape™ Add-On Modules

For extended measurement tasks and further analysis the μShape™ software offers

a great variety of add-on modules which can be added by the user if needed.

Among these are:

Analysis of aspherical surfaces in spherical or CGH setups

Analysis of cylindrical or toric surfaces

External communication interface for controlling the interferometer by

external programs, e.g. in an automated system

Measuring of homogeneity of glass plates

MTF analysis of focal or afocal optical components and systems

Measuring multiple apertures in one shot, e.g. on polishing heads

Statistical analysis of multiple sub-apertures at the same time

Prism and wedge measurement and analysis

Considering known sample deviations

Special μShape versions

In case were the powerful μShape™ Professional software does not meet the

customers' needs `offers special and customized software solutions.

μShape FastFringe Software

The FastFringe Software is designed for interferometers without phase-shifters. The

measurement results are calculated by a static fringe analysis from a single

interferogram. The analysis features are very similar to the μShape™ Professional

with only a few exceptions not useful for non-shifting setups.

μShape Customized Software

The Customized version is an individual version of the Professional Software, which

is specifically designed and created for special customer needs. A variety of add-

on modules are available, enabling to extend the functions of the software.

Customized analysis and display functions, add-on modules or exclusive modules

for customer specific measuring tasks are provided with the customized version of

the software.


μShape™ Generic Software Package for Third-Party Interferometers

The μShape Generic Package can be used with the majority of commercial

phase-measuring interferometers or individual interferometer setups.

Each package includes drivers for nearly all kinds of camera interfaces and

optionally a piezo-element preamplifier.

Phase shift software:

The phase shift software is extremely versatile and allows information to be

obtained from different parts of the optical surface under test. These display

formats can be extended to all measured data, such as aberration fields, MTF

and slope field. Results can be displayed directly in terms of ISO and DIN

standards. Phase measuring interferometry is a more accurate technique than

static fringe analysis since it offers higher density and uniform sampling of the

interference pattern, and better phase resolution.


Key Features:

Software operates within Windows™.

Capability to evaluate both components and systems.

Full analysis of circular, multiple, low-contrast and null fringes.

Macro programming facility allows repetitive testing routines to be set up.

Reference subtracts.

Multiple fringe unwrapping algorithms

Multiple aberration polynomial sets for analysis

Diffraction and geometric analysis

Derivatives and Integrals

Complex masking including unlimited mask groups


Static Fringe Analysis

A variety of static fringe analysis software packages is available. Static fringe

analysis typically offers an accuracy of around lambda/20 and has the benefit

that the software results can be verified manually for simple peak to valley

measurements. Software offers far more sophisticated analysis including

calculation of the rms wavefront deviation, and other derived functions such as

the Strehl Ratio, MTF, Point Spread Function and Encircled Energy Function. The

wavefront shape is often approximated by fitting Zernike coefficients to the

available data, enabling the calculation of Seidel Aberrations. The software can

also flag pass/fail criteria based on irregularity, power, peak to valley wavefront

value and rms wavefront aberration, homogeneity.

Key Features :

Pass/fail criteria; irregularity, power, PV, rms.

Low cost analysis of open or closed fringes.

Full wavefront analysis including MTF, PSF, slope error.

Zernike analysis up to 49 terms.

Reference subtract.

Fiducials and image transformations

Measurements: Wavefront, Wedge, Angle, Prisms

3-Flat Test, Two Sphere Test, Homogeneity


Typical IR Interferograms captured using our system


INFRARED II Dual IR Standard Accessories:

■Aperture converters to increase the 15mm output beam diameter

■ Reference flats (λ/20)

■ Transmission spheres (λ/10)

■ Reference spheres (λ/20)

■ Diverging lenses F#:0.75, F#:1, F#:3,

■ Collimating lenses

■ Off-axis parabolas

■ Attenuators

■ Vertical configurations


■ Upward/downward looking options

■ Static/ phase fringe analysis system

■ Phase shifting accessory

■Refractive collimator (100mm aperture)

■ Optical rail with length ≥ 1.5m for ROC measurement

■Beam expander 50 mm/ 150mm/200mm

■Beam expander 300mm

■Transmission sphere f/1

■ Transmission sphere f/2




Precision mount 2 axis (tilt)

■Compact precision mount 5 axis

■ Large precision mount 2 axis (tilt)

■ Large precision mount 3 axis (tilt)

■Large precision mounts 5 axis xyz)

■ Three Jaw Chuck, 150mm

Reflective Beam Expander

The reflective beam expander accessory is designed for the analysis of large

optics using the INFRARED range of infrared interferometers and can be used

both in the 3-5 micron and 8-12 micron wavebands.

The unit is produced in collaboration with Optical Surfaces Ltd and features a

Newtonian configuration not a Galilean configuration to provide an

intermediate focused image for efficient relaying of optical pupils, which is

essential at longer infrared wavelengths.

The reflective beam expander is a robust, standalone unit which can be bolted

to an optical bench with height adjustment for fine alignment.


It contains a matched pair of permanently aligned aluminum mirrors, complete

with magnesium fluoride protective coatings. It has a wave front accuracy of

λ/10) in the 3-5 micron waveband, with output apertures of 150 mm and 200

mm as standard, although other sizes are available.

For further information about Infra-red interferometers and their applications

please contact our sales department.


13/F, Culturecom Centre,

47 Hung To Road, Kwun Tong, Kowloon, Hong Kong

FAX: +852 8161 7033

Email: [email protected]

Web: www.nextgenn.net

for performance testing of infra-red materials and optical ii dual ir interferometer data...

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