Technical questions

Samples
1. What are the smallest objects SARFUS can image or detect?
  
  SARFUS being a highly sensitive imaging/detection tool, its capabilities are as follows :
  - Nanometric film or layer (1D) down to 0.3 nm in thickness;
  - Nanotubes, nanofibers... (2D) down to 2 nm in diameter;
  - Nanoparticles... (3D) down to 20 nm in diameter.
  
  Nb: The detection limit is sample-dependent.
  
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2. What classes of materials can SARFUS address?
  
  SARFUS can characterise all manners of materials (organics, minerals, oxides, metals...). If you are interested in measuring the optical thickness of nanomaterials, know that only transparent samples (i.e., refractive index free of imaginary part) can be measured for optical thickness. Materials such as organics, polymers, oxides, nitrides and so forth fall into that category. This option is called SARFUS mapping. It is not yet possible to measure metal film thicknesses. In addition, some precautions should be taken as regards samples that change the optical polarisation of light and samples (pigments, for example) that change the RGB components of the optical response.
  
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3. Must I label my samples prior to ‘depositing’ them onto a Surf?
  
  No, not at all. The technique is totally non-label. You directly deposit your sample onto a Surf.
  Note that SARFUS is compatible with fluorescence, superimposition of a SARFUS image and a fluorescence image often leads to interesting, thought-provoking information.
  
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4. How to get my samples onto a Surf so that I can characterise them optically?
  
  Use the same process your are used to performing when you experiment with your usual sample substrate (glass slide, silicon wafer, mica sheet and so forth). The easiest way is to start off with a suspension of your sample and then carry out drop deposition, dip-coating or spin-coating. Deposition in an environmental chamber or reactor is also possible (CVD, PVD, plasma...). These are just a few examples we are familiar with, you can come up with something different that suits your needs best, alternatively you can contact us for tips or devising other ways.
  
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Surfs
1. How do Surfs enhance sample image contrast?
  
  SARFUS detects the change in polarisation state of the light reflected off of a specimen. A white light beam passes through a linear polariser to produce a linearly polarised light source which, after reflection from a sample, experiences a change in polarisation that becomes elliptic. Finally, the reflected beam passes through an analyser crossed with the polariser. Specific substrates, called Surfs, are designed to eliminate unwanted reflected light originating from the substrate that masks the presence of nanomaterials at their surface (in short, they generate a dark background) when a sample is being observed in crossed polarisation. Surfs achieve that by not changing the polarisation state of reflected light. The light emerging from the analyser is thus only due to the specimen’s presence.
  
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2. What is a Surf made of?
  
  Surfs consist of a silicon or glass plate supporting a stack of highly-controlled nanometric layers.
  
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3. How big is a Surf?
  
  The basic lateral dimensions of a Surf are 10mm x 10mm. Other lateral sizes are available on request.
  
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4. What are the available Surf top layers ?
  
  SiO₂, TiO₂, SAMs -terminated (CH_3-, NH_2-...) SiO₂ or TiO₂, polymers (polystyrene, polycarbonate...) are amongst the materials we make our topmost layers from (feel free to contact us to find out what the available top-layers are). Likewise, in case the top layer you want is not in our list of top layers, we urge you to contact us and we will see if we can develop it for you.
  
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5. Are there Surfs for observation in water/dilute aqueous solution?
  
  Yes, there are. We offer Surfs for observation in water with different top layers: SiO₂, TiO₂...
  
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6. Are there Surfs compatible with inverted optical microscopes?
  
  Yes, there are. We commercialize transparent Surfs with glass as supporting plate material, especially designed for inverted microscopes. They come in individual sheets or inserted into a Petri dish.
  
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7. Can I pre-treat Surfs before transferring samples onto them?
  
  You certainly can. Amongst other processes, acid treatment, UV-ozone, plasma are applicable to a Surf.
  
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8. Can I reuse Surfs by cleaning them?
  
  You can but you must know that owing to their high sensitivity, Surfs are not easily cleanable (down to nano-remnants, that is). Even with clean solvents, there always remains nanometric traces on the surface of a Surf. Properly filtered cleaning reagents are a must use if you want to give yourself a chance to reuse Surfs.
  
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9. What is the lifetime of a Surf?
  
  Surfs are protected with a particular adhesive (it leaves no residuals after getting peeled off) that shields the top layer from atmospheric particles. Thanks to this protection, a Surf’s lifetime is unlimited. Do not remove the protective film before it is time to prepare your samples.
  
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10. How robust and stable is a Surf to processes such as heat treatments and chemical aggressions?
  
  Surfs are made of different optical layers and top-layers; they show varying resistance to temperature, radiation and chemicals. Most of the Surfs exhibit good resistance to heat (up to 700°C), to acid/base attack (piranha activation for example), to most of the usual solvents. For each Surf (each Surf ?), a data sheet with resistance data is provided.
  
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Visualization
1. Can I use my own optical microscope?
  
  Yes, you can if you use a reflected light microscope with - at least - bright field as an illumination technique, however surface-enhanced ellipsometric contrast (SEEC) microscopy truly shines in a particular optical configuration (X-pol). The thinnest films (typically thinner than 2nm) may require X-pol to be measured. If you are wanting to image fiber or particle-like nano-objects with two dimensions below the diffraction limit (and not films either as large coatings or micro-patches), you should aim for DIC microscopy and we will help you make the necessary additions to your optical setup. A true SARFUS imager can switch between all these illumination techniques depending on the sample to be imaged. We will put up some series of pictures that illustrate this fundamental point more proficiently than words do in the near future.
  
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2. What do I need to carry out SARFUS imaging?
  
  Unless you want to image or measure the most challenging systems (see section a.), your reflected light microscope is probably SEEC-compatible and all you need is Surfs.
  
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3. Can I control the environment of my samples (temperature, atmosphere...)?
  
  Yes, you can. As for standard light microscopy, you can use heating plates, environmental control chambers and so forth.
  
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4. How much time can I keep my sample on a Surf?
  
  You can keep your sample on a Surf as long as you want but it is recommended to keep it in a clean area to avoid particles contamination by ambient atmosphere. A nicely sealed, under vacuum dessiccator with silica gel at the bottom is an excellent place to start but you can think of other equivalent solutions (clean room, large Petri dish wrapped with parafilm, etc).
  
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5. Is the system safe?
  
  Yes, the system is completely safe (no laser, no high-voltage, no labelling, no marker...).
  
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Measurement
1. What do I need to make optical thickness measurements?
  
  You either need the SARFUS Mapping Lite plug-in to go along with your own optical setup and colour camera if you want to make measurements in air of nanometric films. If your metrological needs are even more demanding (subnanometric films, materials of high refractive index such as oxides or nitrides, measurement in aqueous medium) or prefer to go for a stand-alone station that takes care of everything from data acquisition to processing and even publication-worthy graphical representation, you will have to choose SARFUS Mapping.
  
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2. Is your set of step height standards certified?
  
  Yes, it is. We provide sets of step height standards traceable to PTB (Germany) following EN ISO/IEC 17025 norms. PTB: Physikalisch-Technische Bundesanstalt (www.ptb.de) is the National lnstitute for Science and Technology and is the highest metrological authority of Germany.
  
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3. How reproducible or repeatable are optical thickness measurements made by SARFUS mapping?
  
  Repeatability measurements based on 30 measurements according to the ISO standard 17025 lead to a repeatability value as good as 0.3nm (U(k=2)).
  
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Synergy with others techniques
1. Why is it beneficial to use SARFUS simultaneously with or alongside other techniques?
  
  Combining SARFUS with others techniques is particularly appealing to those who believe in a multidisciplinary approach to experimental research (optical and mechanical/spectral investigations, for instance), it is also highly desirable to facilitate pre-localisation of nanometric samples (for example pre-localisation of nanometric structures, biochips, nanotubes before AFM topographic mapping...). This way you save consumables, sometimes expensive materials, invaluable time and put yourselves in a position to experimentally study the exact same region of interest however small via a variety of techniques.
  
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2. What are the techniques that can be combined with SARFUS?
  
  All techniques that include or can include optical microscopy on a single platform such as AFM, Raman, FTIR but also vacuum surface analytical techniques such as XPS, Auger, SIMS that cannot. Regions on interest will be identified and located by SEEC microscopy outside the vacuum chamber (samples must sit on a SURF, standard or marked) and then inside the chamber the incident beam will be shone directly on the relevant location thanks to the SEEC-obtained coordinates. It will be more accurate with a motorised stage and/or a marked SURF.
  
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Sales

Demonstration
1. Do you put together SARFUS demonstrations for people interested in seeing this technology in action?
  
  Yes, we do. We can offer you a live Skype demonstration wherever you are on the planet. Please do fill in the form to make a formal request.
  
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2. How to test out the capabilities of SEEC microscopy with my own optical microscope?
  
  You now have the possibility to purchase boxes of 9 SURFs (6 for T-SURFs). This package is inexpensive enough to tempt the least convinced of experimentalists out there to have a go at it without killing a budget – however small – while providing a sufficient number of substrates to give them a good feel for what the technique brings to the table in a variety of situations.
  
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Quotations
1. How expensive is a SARFUS system?
  
  You can ask for a Price list here.
  Substrates are available online at http://www.nano-microscopy.com.
  
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Installation/Training
1. Are there specific requirements to accommodate a SARFUS system?
  
  No, not really. All you need is a mains socket and some space to fit the tool and computer in.
  
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2. Do I need formal training to use SARFUS?
  
  SARFUS Imaging is straightforward enough to carry out that no training is required. For SARFUS Mapping on the other hand, a more involved endeavour, we systematically offer a thorough one-day course in your own facility that will enable you to exploit the fullness of SARFUS technology right away. SARFUS Mapping Lite is in between. It is almost as simple as SARFUS Imaging and the package you get as a customer contains a comprehensive user's manual to the software that converts simple camera snapshots into accurate 3D maps of nanofilms. We also help you characterise your optical setup metrologically when you start making measurements.
  
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Customer support
1. Do you provide any customer support?
  
  Yes, we do. In particular, we are committed to answering all customer requests within 24 hours (open day) at the most.
  
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FAQ

Technical questions

Sales