Technical Notes

Description: A time of flight spectrometry technique, allowing the analysis of biomolecules and large organic molecules

Recommended Product: Stanford Research NL100

Goal: to know  the molecular weight distribution of a polymer sample Preparation of the sample: Solved in a solvant and mixed with a special component which absorbs UV (matrix)

Typical MALDI layout

Description: A remote-sensing technique that uses a laser light source to probe the characteristics of a target

Recommended Product: Quantel Brilliant

Atmosphere control Density Temperature Wind Pollution... Distance,  speed measurement Rayleigh, Mie scattering Raman scattering Fluorescence Doppler shift

LIDAR: Principle

The laser light, back-scattered by particules, is collected by a telescope. The time delay between emission and reception represents the distance (time of flight). The intensity is an image of the particules density Laser/telescope unit is mounted on a mobile system

LIDAR: Typical set-up

LIDAR: Applications

Anhui Inst. Of technology, China

• Localisation of pollution emission
• Measure of the limit layer of the atmosphere
• Measure of the diffusion of pollution clouds
• Ozone hole

• Aerosol measurements

“Nadezhda”, Russian ship sailing in Singapore area Measure of the atmosphere around the world

Laser Brilliant mounted on emission/reception telescope

LIDAR in operation

LIDAR: Commercial Systems

Elight Leosphere Polis Raymetrics

Description: A form of atomic emission spectroscopy in which a pulsed laser ablates a small amount of material from the sample's surface, the light from which is captured and analysed by a spectrograph

Recommended Product: Big Sky Ultra

Laser-Induced Breakdown Spectroscopy (LIBS) is a type of atomic emission spectroscopy in which a pulsed laser, generally a Q-switched Nd:YAG laser, is used as the excitation source.

The output of the laser is focussed onto the surface of the material to be analysed. The high power density at the surface (in excess of 1 Gigawatt per cm2) causes a fraction of a microgramme of material to be ejected from the surface (ablated) and a short-lived, highly luminous plasma is formed.

 
A typical LIBS experimental set up. Image courtesy of Applied Photonics .

The ejected material in the plasma dissociates into various ionic and atomic species. As the plasma cools, the excited ions and atoms emit optical radation. This emitted optical radiation is then analysed by a sensitive spectrograph and provides information about the composition of the material.

 
LIBS spectrum of gold ore. Image courtesy of Applied Photonics .

LIBS has many advantages over other techniques as it is virtually non-destructive (only a minute amount of material is ablated) it can be acheived remotely (up to 100m away) and the sample requires no preparation. Because of these advantages, LIBS can be particularly useful when working with hazardous materials or in harsh environments.

We work closely with Applied Photonics , who have succesfully used Big Sky Ultra lasers and Quantel Brilliant lasers in their LIBSCAN  and ST-LIBS  systems.

For more information about the analytical capabilities of LIBS, please visit Applied Photonics LIBS capabilities page . This is an ever-expanding database of information of LIBS data and spectra obtained from each element in the periodic table.

Description: Alignment of parts or machinery using a laser spot, cross or line

Recommended Product: Laserex Laser Diode Modules

Several properties of lasers make them perfect for alignment applications. They emit coherent light that can be well collimated into a straight, continuous, highly visible beam. Wherever high accuracy alignment of a sample, machine part etc is needed, the laser is the perfect tool.

The addition of a line generating optic will provide a thin light sheet that can further be used for 3D alignment and surface profiling. Below are some examples of were our lasers are used in industrial, automotive and manufacturing environments.

Every part’s surface is made up of texture and roughness which varies due to manufacturing techniques and the part structure itself. To understand a component’s surface and to control the manufacturing process to the degree required in today’s modern world, it is necessary to quantify the surface in both two and three dimensions.

Surface texture parameters can be grouped into these basic categories: Roughness, Waviness, Spacing, and Hybrid.

An Introduction to Zygo Metrology Solutions for improving product quality and reducing cost

The Zygo Metrology Group at Lambda Photometrics delivers precision industrial metrology solutions for QA and Statistical Process Control in manufacturing to help reduce the cost of defects and ensure your customers receive the best possible engineered components. Non-contact metrology from Zygo for manufacturing and R&D provides you with the tools to do the job quickly and effectively whilst providing the flexibility to adapt to your needs as your customers demands change. At Lambda Photometrics we recognise that our customers are faced with growing pressure to improve the surface form, finish and performance of components they manufacture and we have developed leading edge metrology solutions to help deliver such capabilities to you. Our high speed and precision metrology tools are capable of measuring: 3D surface profiles, roughness, texture and machining marks, step height, features, cone angles, wear volume, flatness, surface form, radius of curvature and many other parameters associated with precision engineered components, optics and MEMS (micro-electro-mechanical systems).

A wide range of industry sectors including automotive, medical, optics, IT, semiconductor, aerospace and precision engineering have benefited from working with Lambda Photometrics:

Improved component quality Reduced waste Reputation for performance and quality from 1000’s of installed units worldwide Established over 35 years with experience to match Manufacturing and R&D metrology solutions tailored to your needs Installation and support on site Training to ensure you get the most from your metrology tool Measurement service for smaller runs of components or R&D

If you have a pressing metrology issue and would like to know if we can help, try us out and send us a component sample to be measured, for more details see our sample measurement programme

What we measure

Precision metrology for a wide range of surfaces and in some cases films encountered in engineering and science. Our solutions allow surface profiles, form, flatness, waviness, texture, roughness, machining marks, material features and finish to be measured using high speed non-contact imaging technology. This delivers:

• Non-contact measurement of complete surfaces in 3D not just point samples or a line profile but height information across a whole 2D image so you do not miss a thing
• Powerful process software with easy to use interface allows you to extract familiar data such as 2D profiles at will and in any orientation
• Capture data at far higher speeds than can be achieved with contact methods such as CMM or stylus profilers. Up to a million data points can be captured in seconds
• To rapidly take the 3D data captured and allow comparison with conventional contact metrology
• Offer far higher precision particularly in the height dimension than can be achieved with conventional metrology tools, typically down to 0.1nm
• Allow complex image processing of data to perform sophisticated QA measurements or extract specific quantitative data from the measurement e.g wear volume
• Automate the process to reduce or eliminate operator intervention
• Provide rapid measurement of serial components for factory floor 100% inspection

Typical measurements:

• Surface form and profile
• Departure from spherical and planar form
• Flatness
• Radius of curvature measurement for concave and convex surfaces
• Volumetric wear
• Surface features and machining marks
• Roughness and a wide range of texture measurements for surfaces including Ra, Rpm, Rz (conforms to new ISO standards). For a full list of measurements download this document Texture
• Waviness and a wide range of parameters user selectable through filters
• Cone angle and recessed features
• Step height and multiple surfaces
• Thin and thick films

Traceability to certified standards

Our metrology tools provide unrivalled performance that is traceable to certified standards to ensure you achieve the highest accuracy, reproductibility and repeatability in your application. For more details download this document standards measurement.

Other typical applications include:

Orthopaedic implants

Measurement of radius of curvature Roughness and other texture parameters Machining and wear marks Wear volume

Contact Lenses

Surface form Radius of curvature Roughness

Diesel Injectors

Flatness Roughness Multiple surfaces and step heights Feature dimensions Cone angles Recessed features

MEMS - Micro Electro Mechanical Systems

Deflection & Dynamic measurement Roughness Flatness Step heights Multiple surfaces Film thickness

Data storage

Surface quality and defects Flatness Runout

The tools we use

The GPI, is a Fizeau type interferometer system coupled to an electronic camera and computer system for control and image processing.

• Non-contact high speed imaging metrology tool
• Surface form, flatness and measurement of spherical components (both convex and concave)
• Measures deviation from form of a complete surface area typically from several sq cm to hundreds of sq cm in seconds
• Measurement is guaranteed to better than λ/10 (63nm) across the whole viewing aperture of the instrument, the resolution of the instrument is far higher. Higher performance to better than λ/100 (6.3nm)has been demonstrated in some applications
• Radius of curvature of both convex and concave components to several microns
• Simple user interface for fast and easy measurement even by unskilled operators
• Can be automated and placed in protective housing for production and shop floor environments
• Built in environmental noise monitoring

The NewView, a scanning white light interferometer system incorporating a microscope objective lens, led light source, electronic camera and computer system for control and image processing

• Non-contact imaging metrology tool, captures up to a million 3D surface data points at high speed
• Measures roughness, texture, flatness, surface height, feature dimensions and thin films with unprecedented performance over conventional metrology tools
• Wide range of built in Roughness parameters from Ra to Rz and other texture parameters
• Typically measures sub sq mm to several sq cm
• Repeatable surface height measurement to 0.1nm
• Ability to measure film thickness, typically from 1 to 75 microns
• Wide range of accessories that also allow measurement of difficult recessed or concave components and features (using super long working distance objectives)
• Simple user interface embedded with powerful metrology applications for rapid and easy measurement
• Can be automated and placed in dedicated protective enclosure for application on factory and shop floor environments
• Built in environmental noise monitoring

How they work

There are two components to the metrology tools we provide, the hardware, comprising the instrument with PC and frame grabber and the software that controls and processes the data from the system. The combination of hardware and software provides fast and powerful metrology tools that deliver automated measurement solutions for QA and R&D in a fast and flexible way.

We use and supply two key instruments, the GPI and the NewView, for surface and profile measurement both driven by a common software package known as MetroPro. Both instruments are non-contact interferometric imagers that provide a 3D image of a surface to a very high degree of precision and with very high speed compared with conventional mechanical systems. Both provide a snap shot of the surface which when processed by the software allows you to extract a wide variety of parameters about a surface including making comparison with conventional measurement techniques. In the case of manufacturing this allows for automation and 100% inspection of components. For R&D the fast turnaround coupled to an easy to use interface makes productivity and metrology fast and accurate and with a precision far above mechanical methods this allows you to explore future capabilities and options.

The GPI interferometer comprises a laser light source, optics for focussing, expanding and collimating the beam and a camera for recording interference fringes. The GPI can be used for measuring flatness using a precision Transmission Flat or spherical surfaces using a Transmission Sphere, in this particular example we shall consider the measurement of a spherical surface. The Transmission Sphere used for this measurement is a focussing lens taking the collimated (flat wavefront) laser beam and focussing it into spherical waves that converge onto the part to be measured. The transmission sphere is a precisely formed system of optics that for most applications can be considered to generate a perfect spherical light wave converging on the part under measurement.

GPI Basic Operation

Some of the collimated light on striking the curved surface of the transmission sphere (a glass/air interface) is reflected back into the instrument to create a reference beam of light. In this example a spherical sample has been placed in proximity to the Transmission Sphere such that the spherical wavefronts impinging on the surface strike the surface at a normal and hence the light is reflected back along its original path and into the instrument. The reflected light from the part under measurement and the reference beam are combined to create an interference pattern that is detected by the camera.

During a measurement the Transmission Sphere is translated linearly along the optical axis with a piezo electric device to create a moving fringe pattern that is interpreted by the computer system to show the deviation of the part under test from an almost perfect sphere. The system displays these departures from spherical form using a colour coded image plot and also an oblique surface form plot, click here for examples of a spherical hip socket. The same principles can also be applied to the measurement of flat surfaces using a Transmission Flat as the reference.

The NewView scanning white light interferometer has similar elements and operation to the GPI. It employs optics in the form of a modified microscope objective, a light source, in this case an incoherent broadband LED light source is split at the objective so that some of the light passes to a reference mirror and some is focussed onto the surface of the sample under measurement. Light from the mirror and the sample surface are reflected back into the instrument and imaged onto a camera. If the distance from the light splitter to the mirror and from the splitter to the surface are equidistant so that there is no optical path difference (OPD) then the camera will observe an interference pattern. This occurs when the objective is held so that the focal plane of the objective lies in the same plane as the surface.

NewView Basic Operation

In order to perform a measurement of the surface observed by the field of view of the objective, the objective lens is translated vertically and linearly so that the focal plane moves through the entire height range of the surface being measured. As it does so the interference fringes will move and follow the height profile of the surface and this information is processed by the instrument to calculate the height profile to a very high precision. If we take the simple example of a spherical surface and the objective moving downwards then the interference fringes will appear as a small set of concentric circles emanating from the top of the sphere as the focal plane of the objective intersects it.

The concentric fringes will then grow larger as the focal plane moves and intersects the sphere lower down. The NewView is able to measure and view an image field dictated by the field of view of the objective lens, for example a 10x objective with a resolution of 1.18 microns is able to observe an area of 1.1mmx1.1mm. As with the GPI the MetroPro software processes the interference data to create a colour coded height profile of the surface under measurement, click her for an example, To measure larger areas there is a facility on the NewView to stitch image fields together. A motor driven stage allows the system to move the surface under inspection a step at a time and in raster fashion to allow relatively large planar surfaces to be measured.