Characterisation, Measurement & Analysis
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Knowledge Base

Welcome to the Lambda Knowledge Base

  • Measuring Index and Thickness of Silicon Thin Films

    The Metricon Model 2010/M provides rapid and accurate measurements of thin films of silicon on cladding layers of lower index materials such as SiO2 or bulk fused silica/glasses for wavelengths at which the films are transparent (typically 1100 nm and above). Convenient 30-second measurements can be made with a single prism for sample thicknesses over the 1.4 -3.5 micron thickness range. Thinner films are measurable if two prisms are employed (with each prism used to find a single mode) but typical measurement time increases to ~5 minutes because of the time required to change prisms.

     

    Measurable thickness range using one prism:
    Thickness and index can be measured for films in the ~1.4-3.5 micron thickness range. In addition, if approximate thickness is known (+/-20%), index and exact thickness for layers as thin as 0.8 micron can also be measured with a single prism.

    Measurable thickness range using two prisms:
    Thickness and index can be measured for films in the 0.3-1.4 micron thickness range.

    Note:
    The above limits are for 1550 nm wavelength but measurable ranges are similar for 1310 nm

    Waveguide loss measurement:
    Loss can be measured for modes with effective index in the ~1.5-3.38 range.

    Other wavelengths:
    Model 2010/M systems with built-in ~1310 and/or ~1550 nm wavelengths are available from Metricon. Model 2010/M systems can also be configured with a port for use with any laser supplied by the user with wavelength >1100 nm.

    Please contact Lambda Photometrics/Metricon with approximate thickness of silicon layers to be measured to determine which of our four silicon prism types (covering different effective index ranges) are best for your needs. For other very high index (>3.3 ) films, please provide approximate index and thickness and we will advise about measurability.

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • Measuring Refractive Index of Liquids Inside Sealed Containers

    Metricon’s Model 2010/M accurately and rapidly measures refractive index of liquids inside sealed containers such as glass vials/bottles, allowing rapid and non-destructive measurement of solution concentration for quality control purposes. Matching liquids are not required between the measuring prism and the wall of the container. If a label is present, the only requirement is that there be a gap of 2-3 mm between the label ends (i.e. the label cannot extend completely around the circumference of the bottle). Excellent results have also been obtained using amber containers and measurements of liquids inside containers of other colours should be possible by appropriate choice of the measuring wavelength.
    The principle of measurement is shown below. A container with the liquid to be measured is brought into intimate contact with a measuring prism of index np using a pneumatically-operated coupling head. Collimated laser light is directed onto the base of the prism and the light also refracts into the wall of the container. The prism and container are mounted on a rotary table which can be turned under computer control to change the external angle of incidence θ on the prism so that the laser beam scans through the critical angle for the container-liquid interface:

     

    When the beam strikes the container-liquid interface above the critical angle, the light reaching the interface is totally reflected to the photodetector mounted on the opposite side of the prism. However, as the external angle θ changes, θc, the angle in the container wall, drops below the critical angle for the container-liquid interface and some of the light refracts into the liquid causing a sharp drop in the intensity reaching the photodetector. The angular location of this sharp drop (θCRIT ) is easily found by the Model 2010/M’s pattern recognition software:

    As the light refracts from the prism into the container wall and then into the liquid, from the law of refraction (Snell’s Law) the following equations apply:

    nP*sin(θP) = nC*sin(θC) = nL*sin(θL)

    By eliminating the middle term, this equation is easily simplified to
    nP*sin(θP) = nL*sin(θL)

    At the critical angle sin(θL) = 1 and the index of the liquid is
    nL = nP*sin(θPCRIT) (1)

    Where θPCRIT, (the angle of incidence on the base of the prism at the critical angle for the container-liquid interface), is easily calculated from θCRIT (the external angle on the prism at the critical angle), nP (the prism index), and α (the prism angle).

    Equation 1 above shows that the measured index for the liquid is independent of the index of the container wall and depends only on the prism index (which is known to high accuracy).

    SPECIFICATIONS
    Accuracy, precision, and repeatability:
    Sample measurements at a single point on the exterior of a bottle/container are highly repeatable – typically ±.0.0001. However, usable accuracy and precision are both worse (typically ±.0.0005) because of non-parallelism of the container walls which can cause a slight shift in the location of the observed critical angle. The expected accuracy/precision for applications using a specific container type is easily determined by measuring the index variation of a known standard (such as distilled water) for several individual containers at different axial and circumferential locations on the container exterior.

    Index range of liquids measurable:
    Index of the liquid to be measured must be ~.05 less than the index of the container. Typical index of glass used in bottles/vials is ~1.51 so this spec is easily met by most liquids/solutions.

    Measurement wavelength:
    The standard wavelength provided with the
    Metricon 2010/M system is 637 nm but a different wavelength can be substituted if desired by the user. For most monitoring/quality control applications a single wavelength should be sufficient, but 2010/M systems can also be configured with up to six wavelengths if it is desired to measure at more than
    a single wavelength.

    Measurement time:
    ~20 seconds.

    Left: Measurement of DI water index at 633 nm wavelength = 1.3318 (expected value 1.3315) Right: Typical bottles/vials measurable

    Please contact Lambda Photometrics/Metricon with approximate thickness of silicon layers to be measured to determine which of our four silicon prism types (covering different effective index ranges) are best for your needs. For other very high index (>3.3 ) films, please provide approximate index and thickness and we will advise about measurability.

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • A History of ZYGO Optical Profilers

    Some brief notes on the systems and technology over the years:

    Heterodyne profiler

    Maxim 5700: Micro Fizeau, tip/tilt in the head, PSI (Phase Shifting Interferometry), HPUX system controllers.

    Maxim 3D: PSI, 2 wavelengths for rougher surfaces, HPUX system controllers.

    NewView 100: The first Scanning White Light Interferometer (SWLI) from Zygo, uses Frequency Domain Analysis (FDA) to achieve high resolution over the entire scan range. 100 µm scan using PiFoc, open loop, finite conjugate objectives. HPUX system controllers. Standard microscope stand. Wyko RST was around during this time.

    NewView 200: Switch to infinite conjugate objectives that work with all future NewView’s, Nexview’s and ZeGage’s. Open-loop and closed-loop PiFoc piezo scanner, 100 µm range. HPUX system controllers. Standard microscope stand. Extended scan implemented.

    NewView 5000 series: Introduction of “A” frame designed using Finite Element Analysis (FEA) to minimise vibrations.  Used on all subsequent NewView systems.  Has extended scan to measure up to 5000 µm. Variable zoom. End of PC upgrade route due to frame-grabber board no longer being available.

    NewView 6000 series: Introduction of CAN bus electronics and away from Type II board. Fixed zoom and zoom turret available (NewView 6300).

    NewView 600: Low cost single objective system, manual stages.

    NewView 700: Low cost single objective system, manual stages.

    NewView 7000 series

    ZeMapper: Available after ZeMetrics acquisition. Good for large area parts such as hard disk drive substrates. Used ZeMaps software. Discontinued 2014.

    ZeScope: Available after ZeMetrics acquisition. Good for large volume parts such as larger engineering parts. Used ZeMaps software. Discontinued 2014.

    ZeGage: Jointly developed by Zygo and new ZeMetrics team. Used NewView optical head and ZeMaps software. Z scanner is non-piezo based. Migrated to new Mx software.

    Nexview: Flagship optical profiler from Zygo, and first to use new Mx software. Introduced many new features such as crash protection, colour imaging, the “More Data” concept, SmartPSI, oversampling, new 5.5x and 2.75x objectives, parfocal imaging, and full automation capability (including motorised filters and stops).

    NewView 8000 series: Introduces the new Mx software to the NewView family. Has many new features in common with the Nexview including crash protection, the “More Data” concept, oversampling, new 5.5x and 2.75x objectives, and parfocal imaging. Mx facilitates greater automation capability compared to previous profilers.

    ZeGage Pro and Pro HR, NewView 9000, Nexview NX2: Updated range of profilers with a new 1.9 MP high-sensitivity and high-speed sensor. Introduces fast focus technology and smart features such as ‘Find Part’ to automatically and rapidly focus on the surface – even over many millimetres of scan range – and ‘SmartSetup’ which extends the part finder by also detecting the optimal acquisition settings and taking the first measurement. This generation is available for demonstration by Lambda Photometrics.

  • Fischione Model 1080 PicoMill® TEM specimen preparation system

    A guide for preparing TEM specimens for a demonstration of the Model 1080 PicoMill® TEM specimen preparation system at Fischione Instruments.

    The Fischione Model 1080 PicoMill® TEM specimen preparation system is ideal for specimen processing following focused ion beam (FIB) milling. The PicoMill system’s concentrated argon ion beam, typically in the energy range of 50 to 2000eV, excels at targeted milling and specimen surface damage removal. Ion induced secondary electron imaging is used to locate the FIB-produced lamella and then to target the region that will receive low energy milling in either raster or spot modes. Only the lamella is targeted during ion milling. Ion bombardment of the supporting grid is eliminated, which helps to prevent redeposition. The PicoMill system can also remove damage from electro polished or broad beam ion milled specimens.

    CLICK HERE to download the full Model 1080 PicoMill® TEM Specimen Preparation System Application Note.

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • Energy Storage Application Note – Water Splitting

    Among the solar fuel technologies, water splitting is a relatively mature technology that uses renewable electricity and water to product H₂. Storing renewable energy as H₂ is a solution for the intermittency problem of solar cells and wind turbines. Moreover, a large amount of H₂ is produced in non-renewable ways every day for important industrial processes. Replacing that H₂ by the H₂ obtained using water splitting would significantly reduce the CO₂ emissions and its impact on the climate.

    Optimisation of complete electromechanical devices.

    CLICK HERE to download the full Water Splitting Application Note.

     

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • Catalysis Application Note – CO₂ Hydrogenation

    CO₂ capturing and utilisation technologies have the potential of decreasing the CO₂ emissions that cause climate change. Utilisation of CO₂ also allows to directly recycle the CO₂ produced in the industry to make the process carbon neutral and to produce value-added products (fuels and chemicals). Methanol is an excellent product for CO₂ utilisation, since it is already produced world-wide in large scales to be used as a fuel and a solvent.

    Engineering complex active sites with VSPARTICLE tools

    CLICK HERE to download the full CO₂ Hydrogenation Application Note.

     

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • Catalysis Application Note - Fuel Cells Research

    Fuel cells

    Storing electricity into fuels is a promising way to solve the intermittency problem of solar cells and wind turbines. However, in order to start implementing renewable fuels, the conversion process from these fuels back to electricity needs to be carried out efficiently and cheaply. Fuel cells are devises that can convert a great variety of chemical fuels into electricity and can be operated in a wide range of operational conditions (eg. temperatures).  This way, advances in fuel cells research can make renewable fuels a reality, which can play an important role in the energy transition.

    Challenges
    One of the most important components in a fuel cell are the catalysts in the anode and cathode of the fuel cell. The size and composition of these catalysts need to be optimised to overcome common catalyst issues, such as low activity and catalyst poisoning. However, not only the catalyst properties need to be optimised in fuel cells but also the way the catalyst is integrated into the device, which may consist of a gas diffusion layer, catalyst support and a membrane (see illustration below). Proper integration of these components should maximize the ion conduction and mass transport in the catalyst layer. Therefore, in order for fuel cell applications to have an economical and environmental impact on our society, research tools are needed to speed up the optimisation of the catalyst and its integration into a fuel cell device for specific fuels and applications.

    CLICK HERE to download the full Fuel Cells Research Catalysis Application Note.

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • Catalysis Application Note - CO2 Electroreduction

    CO2 Electroreduction

    CO2 electroreduction is a promising technology that uses intermittent renewable electricity and CO2 emissions to product fuels (e.g. methanol) and other economically relevant products (e.g. syngas). One of the great promises of this technology is to recycle the CO2 produced by factories, reducing CO2 emissions and its impact to climate change.

    In order for CO2 electroreduction to play a major role in the energy transition, the main components of a CO2 electroreduction device, the electrocatalysts, need to be optimised to produce fuels or chemicals efficiently and selectively.

    CLICK HERE to download the full Catalysis application note.

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • AN-117 Measuring Insertion Loss and Return Loss of Hybrid Cables in OPL-MAX

    Obtaining connector-level insertion loss (IL) and return loss (RL) for hybrid cables is complicated by the different connector types on either end of the cable. Hybrid cables cannot simply be flipped to test the reverse direction when the reference and device under test (DUT) connectors are no longer compatible. A test setup comprised of the OP940 IL and RL Meter with two detectors, the OP725 Benchtop Optical Switch, and OPL-Max Application Software solves the compatibility issue and allows for hybrid cable testing with high speed, accuracy, and repeatability.

    CLICK HERE to download the AN117 application note.

     

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • How Can You Accurately Test Performance of Hybrid Cables?

    Fibre patch cables, also known as patch cord or jumper cables, are fibre optic cables that are terminated with connectors on both ends. When the connector types on each end are different, the cable is aptly dubbed a HYBRID CABLE. These hybrid cables can serve to link otherwise incompatible infrastructure in existing fibre systems, such as those found in networks or data centres. They can be used to connect newer racks to legacy hardware, in distribution hubs to branch lines from high density panels to the nodes they serve, or to connect between devices from different manufacturers.

    How Can You Accurately Test Performance of Hybrid Cables?
    While the hybrid nature of these cables makes them ideal for these types of applications, it does present some challenges when evaluating the performance of the cables, whether during production or prior to installation. Like most other passive components that are added to networks or data centres, hybrid cables typically need to have both sides qualified for insertion loss (IL) and return loss (RL), along with interferometry and visual inspection.

    The challenge comes from mating the different connectors of the hybrid cable to the reference cables and detectors used to measure IL and RL, which must be done since each side of the cable must be tested. This can be achieved by having twice as many reference cables and detectors, two of each in the case of a simplex cable.

    Tailored Solution for a Challenging Problem
    The OP940 IL and RL meter serves as the base for our simplex hybrid cable test system, built with two detectors to accommodate the different connectors. Introducing the OP725 optical switch allows us to use two reference cables by toggling which cable the light travels through.
    This configuration provides both ease of use and flexibility. Having multiple reference cables connected at once allows the user to test both sides of the device under test without having to swap cables in and out. This particular example uses LC and SC cables, but testing different connector types is as simple as substituting different reference cables. A similar substitution can be done for the adapters on the detectors. In fact, if the different connectors have the same size ferrule (i.e. FC and SC), the configuration can be simplified to use one detector with a universal adapter.

    A Note on Hybrid Mating Adapters:
    While hybrid mating adapters can allow different connector types to be mated together, these types of adapters can cause issues for IL testing. LC to SC mating adapters in particular often induce extra loss into the measurements. The difference in ferrule size between the two connector types makes their connection within the hybrid mating adapter unreliable for IL testing. For this reason, the better approach is to use a different reference cable for each type of connector being tested.

    CLICK HERE to download further information.

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

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