Raman Spectroscopy is a analysis technique based on the interaction of light on the bonds within the material/sample. It is used for sample identification by “fingerprinting” as different material will gives different Raman spectrum. It works by shinning a monochromatic light source (i.e. laser) onto a sample and detecting the subsequence scattered light from the sample which consist mainly of elastic scattered light (Rayleigh scattering) and a very small percentage of inelastic scattered light (Raman scattering). The Raman scattered light is collected and translated into a Raman spectrum which is unique to different materials. This spectrum is then compared to a library of spectrum to identify the sample, much like the finger print search in forensic.
Easiest way is to refer to publicly available literatures, or send us an email. Our scientists will be able to advise based on our extensive experience, else we will request samples so that we can verify that free-of-charge for you, especially for novel materials.
With near diffraction limit design in our optics, when using a 100x objective lens of numerical aperture of 0.9, the spot size is as small as 0.6μm. Depending on microscope makes and lens used, we typically assure <1μm using a 100x lens.
We spent years in selecting and testing various laser maker and their models before settling on the current parts for their high reliability and stability. Typical lifetime of our lasers used are 10,000 hrs, although our earlier models are still working well after 5-6 years in the field.
SERS stands for Surface Enhanced Raman Scattering or Spectroscopy. In the physical form, it comes as a substrate or sub-micro particles. These are used to enhance the otherwise weak Raman signatures by using the resonance plasmonic effect when the suitable Laser is used. SERS substrate or particles are made mostly from Gold or Silver material which suit 785nm or 532nm, respectively, wavelength very well although might varies depending on its design.
One of the key advantage of Raman spectroscopy or microscopy is no sample preparation is needed. Nevertheless, for ease of measurement due to the high spatial selective in Micro-Raman and the short working distance of the objective lens used, the measurement surface should be relatively flat and the sample cannot be too big (i.e. less than 25mm thick) to fit to the microscope.
Raman spectroscopy comes in many favours, from handheld, probe based, to micro-Raman. When high spatial selectively is needed for the measurement, micro-raman is critical. Samples with thin layers (Z) or of small features (XY) needs a Microscope-based Raman, such as monolayer thin-film, 2D materials, ink pigment, inclusion in gemstones, cells and bacteria, etc.
TechnoSpex does not build our Raman database or library as we believed the currently available 3rd suppliers are able to do a much better job. However, with our uSoft-Search plug-in users can build their own library or search commercially or publicly available libraries easily.
uRaman offers 3 common laser wavelength, namely 532nm, 633nm and 785nm. The choice of the laser wavelength is highly sample dependent. For example, 532nm is good for Carbon-related samples while produce high background fluorescence for organic samples, while 785nm works well with Oil and minerals but easily burn black or dark materials. We recommends customers to send us some of their typical samples for testing, especially if they had not done prior Raman measurement on them before.
As a complete system, the uRaman-Ci comes with a Nikon Ci microscope. However, our modular design allows us to adapt to most upright microscopes, such as from Nikon, Olympus, Leica and Zeiss. To ensure compatibilities, besides knowing the existing brands and model we will also need actual photos of the microscope (Front, Sides and back) to avoid surprizes.
uRaman is designed as a modular system that can be easily moved from one microscope (same manufacturer) to another with minimally realignment (if any). It empowers existing upright microscope for MicroRaman spectroscopy without compromising its existing performance. Despite its compact design, uRaman offers comparable performance with the well-known brands, and sometimes even outperforms some models. Please refer to our testimonials page for more comments from users.
Raman Spectroscopy can be used to analyze solids, gels, liquids and gases in organic or inorganic materials. Unfortunately, it is not suitable for analysing metals.
Raman spectroscopy is widely used to determine the presence of a substance in a mixture or solution. For quantitative measurement, the intensity of the Raman signal/peaks can be used to infer the concentration, however, a calibration process is normally needed to determine the concentration level and the corresponding Raman signals/peaks, with highly control environmental parameters to ensure accuracy.