Technology leaders combine expertise for very low-temperature Raman imaging
Ulm, Germany - Haar, Germany
July 20, 2021
Raman imaging innovator WITec GmbH and cryogenic microscopy specialist attocube systems AG have jointly introduced cryoRaman. This cryogenic Raman imaging system integrates attocube’s leading-edge cryostat and nanopositioner technology with the vaunted sensitivity and modularity of WITec’s alpha300 correlative microscope series. For the first time, Raman imaging at the lowest temperatures in high magnetic fields is now easily accessible with unmatched spatial resolution.
Designed to meet existing and emerging challenges, cryoRaman offers excitation wavelengths from VIS to NIR with optimized spectrometers, 1.6K to 300K operating temperatures, high magnetic fields, patented cryogenic Raman-specific objectives and an exceptionally precise piezoelectric scan stage.
Research on phase-transitions and emergent properties of novel low-dimensional materials will benefit in particular from cryoRaman’s high magnetic field options. The solenoid or vector magnets, with a strength of up to 12T, are ideal for investigating transition metal dichalcogenides (TMDs) and van der Waals heterostructures, and can also help in determining the temperature- and magnetic field-dependence of photoluminescence. Optional modules include precise software-controlled laser power adjustment, multi-wavelength excitation capabilities, automated switching from optical microscopy to spectroscopic imaging, automated spectrometer calibration light source and routines, and time-correlated single photon counting (TCSPC) modes.
cryoRaman also introduces a pair of unique functionalities to cryogenic Raman microscopy: the ability to detect low-wavenumber Raman peaks, and full polarization control in excitation and detection. “Researchers looking at materials in cryogenic environments like to get as close as possible to the excitation wavelength, and they’re very interested in polarization measurements,” said Olaf Hollricher, Co-founder and Managing Director at WITec. “To meet those requirements, we developed features that have no equivalent in the marketplace. In fact, with its imaging capability at low temperatures, level of integration, performance and accessibility to both Raman newcomers and experts, cryoRaman is really in a class by itself.”
The close cooperation between attocube and WITec has produced an instrument ready for an unprecedented range of measurements. cryoRaman incorporates the very latest technology from two trailblazers in their respective fields to establish cryogenic Raman microscopy as a convenient, versatile and indispensable tool for materials scientists.
For more information and a detailed application note, please visit our cryoRaman product page.
WITec GmbH pioneered 3D Raman imaging and correlative microscopy and continues to lead the industry with a product portfolio that offers speed, sensitivity and resolution without compromise. Raman, AFM and SNOM microscopes, combinations thereof, and WITec-developed Raman-SEM (RISE) systems can be configured for specific challenges in chemical and structural characterization through a modular hardware and software architecture with built-in capacity for expansion. Research, development and production are located at WITec headquarters in Ulm, Germany, and the WITec sales and support network has an established presence in every global region.
attocube systems AG is a leading pioneer for nanotechnology solutions in industry and research. The company develops, produces and distributes components and systems for nanoscale applications such as precision motion, cryogenic microscopy, and nanoscale analytics. All products are manufactured in the NanoFactory, the company’s headquarters in Haar, close to Munich. An international team of 200 physicists, engineers, software developers, and product designers work in close collaboration from conception through to delivery. attocube has sales offices in the US and a broad network of worldwide distributors, covering more than 40 countries and 4,000 customers.
- WITec Press Release cryoRaman english (PDF) (309 KB)
- WITec cryoRaman Product Image Close Up View (JPG) (434 KB)
- WITec cryoRaman Product Image Lab Setup (JPG) (604 KB)
WITec combines antibunching experiments with fast Raman and photoluminescence imaging.
Single-photon emitters have quantum mechanical properties that are exploited in quantum technology and information science, including the development of quantum computers and cryptography methods. Nitrogen vacancy (NV) centers in diamonds, single fluorescent molecules, carbon nanotubes and quantum dots are prominent examples of single-photon emitters. In order to identify them in a sample, antibunching experiments are commonly performed.
Antibunching is a quantum mechanical effect that reveals the particle-like behavior of light. It arises because a single-photon emitter can only emit one photon at a time. The minimum interval between photon emissions depends primarily on the excited-state lifetime of the emitter, because a cycle of excitation and relaxation must be completed between two photons. If the signal is split and measured with two detectors, each single photon can only be detected by one of them. Antibunching therefore results in an anticorrelation of the two detectors’ signals at very short lag times (Hanbury Brown-Twiss experiment).
Here WITec in cooperation with PicoQuant demonstrates the integration of antibunching measurements within a confocal Raman microscope. This combination makes it possible to characterize a sample with fast Raman and photoluminescence (PL) imaging and identify areas of interest for subsequent antibunching experiments with the same instrument, a WITec alpha300 Raman microscope. Antibunching measurements are performed in a Hanbury Brown-Twiss configuration, where the signal is split by a 50/50 beam splitter and detected by two APDs. Both detectors are connected to a MultiHarp 150 time-correlated single photon counting (TCSPC) unit from PicoQuant, which records the delay between two single-photon events at picosecond resolution. A histogram of the time differences shows a pronounced dip for very short times, i.e. antibunching, if the investigated structure is a single-photon emitter. Lifetime measurements are additionally possible in this configuration. A 532 nm continuous wave laser was applied for excitation here, but the setup also supports other wavelengths and pulsed laser sources.
We demonstrate this functionality using a sample of diamond micropillars, a fraction of which contain single NV centers. The sample was provided courtesy of Dr. Rainer Stöhr and Prof. Dr. Jörg Wrachtrup from the 3rd Physics Institute at the University of Stuttgart, Germany.
The pillars were first imaged with Raman and PL microscopy. The Raman image represents the intensity of the diamond peak at 1330 cm-1 and reveals the positions of intact pillars (Fig. A). In the fluorescence image, some pillars are particularly bright, indicating the presence of NV centers (Fig. B). By comparing the Raman and PL images, structures of interest can be distinguished from fluorescent contaminations on the sample: intact pillars with NV centers exhibit a strong diamond Raman signal and bright fluorescence (arrows in Fig. A and B), while contaminations lack the Raman signal.
Antibunching experiments were performed at some of the identified structures of interest in order to test for the presence of single NV centers. The resulting correlation curve for one selected pillar is displayed in Fig. C. The histogram has a pronounced dip at a detection time difference of zero. This indicates that the observed micropillar indeed contained a single NV center and was a single-photon emitter. The observed drop in the curve toward longer delay times reveals the presence of a shelving state, which is a well-known phenomenon for diamond NV centers.
The integration of antibunching experiments within a confocal Raman microscope offers many benefits. Such an instrument is capable of carrying out both spatially resolved chemical characterization and quantum mechanical investigations. As demonstrated here, the correlation of Raman and photoluminescence signals can pre-select candidate locations for NV centers to be subsequently confirmed by antibunching experiments. This provides valuable insight and an accelerated workflow to researchers exploring single photon emitters for use in emerging technologies, including quantum computers.
The management team of WITec GmbH is proud to announce that WITec was acquired by Oxford Instruments plc, a UK based company that has a great reputation in the scientific community, and in the future will be part of their Materials Analysis Group. WITec’s founders Dr. Joachim Koenen and Dr. Olaf Hollricher will continue as Managing Directors and the well-established WITec brand will be retained in the new organizational structure.
Founded in 1997, WITec grew from a small university spin-off into the most innovative Raman imaging company. It made exceptional progress in developing microscopy technology and installed more than a thousand Raman, AFM and SNOM systems worldwide.
“We look back on a 24-year track record of making WITec a prosperous and most innovative Raman imaging company. Now that we are joining the Oxford Instruments Group, we look forward to continuing this success together with a strong partner to grow even faster and to use existing synergies to further expand our reach into the range of markets that will benefit from our wide product portfolio,” Koenen said.
“WITec developed ground-breaking solutions in confocal Raman microscopy and correlative Raman microscopy. Oxford Instruments’ key technologies in AFM and scientific spectroscopic cameras with the brands Asylum and Andor puts WITec in an even better position for future developments,” Hollricher added.
Ian Barkshire, Chief Executive, Oxford Instruments said, “We are delighted to welcome WITec colleagues to Oxford Instruments. WITec’s leading Raman microscopy solutions are a great complement to our existing products and techniques. Raman microscopy is an important and widely used technique across academic and commercial customers for fundamental research, applied R&D and QA/QC. The technique is used in conjunction with and alongside our existing characterization solutions and broadens the capabilities that we can bring to existing customers and expands opportunities into new market areas. Providing a broader range of solutions helps us support our customers in facilitating a greener economy, increasing connectivity, improving health and achieving leaps in scientific understanding.”
Ian Wilcock, Managing Director of Oxford Instruments Nanoanalysis and Magnetic Resonance added, “We look forward to working with our new colleagues at WITec to develop new routes to market for their products. WITec’s RISE Raman for SEM product, for example, will ideally complement our own extensive suite of analyzers for electron microscopes.”
WITec will, of course, fulfill its obligations toward existing customers and business partners in the usual manner and the management team will work to make the transition as smooth as possible.
See the official press release from Oxford Instruments here.
- WITec and Oxford Instruments (high-resolution JPG) (3.9 MB)
- Press Release: WITec GmbH joins Oxford Instruments plc (609 KB)
Polymerization reactions are involved in many industrial processes and also occur in everyday tasks, for example during the hardening of glues and drying of paints and varnishes. In order to optimize their products, manufacturers require analytical methods for monitoring polymerization reactions and evaluating the influence of chemical modifications or additives such as catalysts. Here we use Raman imaging for monitoring the polymerization of an air-drying alkyd resin varnish. Such products are commonly used for protective coating of wood and other materials.
The liquid sample was applied to a microscope slide and the polymerization progress was characterized as a function of depth and time using a WITec alpha300 Raman microscope. To this end, an initial depth scan through the entire coating layer was recorded, followed by one per hour at the same sample position for a total of 25. Due to the system’s automated components, no user interaction was required during the entire investigation time of 24 hours. Each of the presented Raman images covers an area of 25 x 31 µm² and consists of 3900 spectra recorded in about 8 minutes.
First, all images were analyzed with the TrueComponent Analysis feature of the WITec Project software. Three components were identified by their Raman spectra and attributed to the liquid varnish, the polymerized product and the glass substrate. The image series clearly shows that the hardening process began at the interface between the air and the varnish and progressed through the sample over time (Fig. A and video). After 24 hours, the sample was almost completely hardened. A small stretch of unpolymerized sample was still present at the glass interface after 24 hours, but was no longer detectable when the sample was re-measured a few weeks later.
The spectra of liquid and solid varnish differed mainly in the intensity of the C=C stretching mode at 1654 cm-1 wavenumbers (Fig. B). As the C=C double bonds react during the polymerization, this peak’s intensity is drastically reduced in the Raman spectrum of the product. This enabled an even more detailed monitoring of the polymerization reaction. While the C=C stretching mode was decreased during the reaction, the C-H stretching mode (ca. 3072 cm-1) stayed almost constant. The ratio of these two peaks thus served as a measure for the polymerization progress. It was quantified for each pixel by peak fitting and the mean of each image line was plotted over the sample depth and the observation time (Fig. C). The graph illustrates in detail how the polymerization progresses over time into the deeper layers of the varnish.
May 6, 2021
Three scientific publications have been recognized by the WITec Paper Award, an annual competition among peer-reviewed articles from the previous year that feature results acquired with a WITec microscope. The exceptional quality of the 115 submitted publications made it particularly challenging to select only three winners. The Paper Awards for 2021 go to researchers from the UK, Turkey and the USA who performed Raman imaging measurements on zebrafish embryos, meteorites and jet engine thermal barrier coatings, respectively. WITec congratulates the winners and thanks all the participants.
- GOLD: H. Høgset, C. C. Horgan, J. P. K. Armstrong, M. S. Bergholt, V. Torraca, Q. Chen, T. J. Keane, L. Bugeon, M. J. Dallman, S. Mostowy, M. M. Stevens (2020) In vivo biomolecular imaging of zebrafish embryos using confocal Raman spectroscopy. Nature Communications 11: 6172 www.doi.org/10.1038/s41467-020-19827-1
- SILVER: M. Yesiltas, M. Kaya, T. D. Glotch, R. Brunetto, A. Maturilli, J. Helbert, M. E. Özel (2020) Biconical reflectance, micro-Raman, and nano-FTIR spectroscopy of the Didim (H3-5) meteorite: Chemical content and molecular variations. Meteoritics & Planetary Science 55: 2404-2421 www.doi.org/10.1111/maps.13585
- BRONZE: C. Barrett, Z. Stein, J. Hernandez, R. Naraparaju, U. Schulz, L. Tetard, S. Raghavan (2021) Detrimental effects of sand ingression in jet engine ceramic coatings captured with Raman-based 3D rendering. Journal of the European Ceramic Society 41: 1664-1671 (available online 2020) www.doi.org/10.1016/j.jeurceramsoc.2020.09.050
For a list of all previous Paper Award winners, please visit www.witec.de/paper-award.
The Paper Award GOLD: Raman imaging of zebrafish embryos
Zebrafish are well-established model organisms in the life sciences and are frequently used for studying embryonic development and various diseases. Håkon Høgset from Imperial College London (ICL), UK, receives the Gold Paper Award 2021 for demonstrating the versatility of confocal Raman imaging for the biomolecular characterization of zebrafish embryos. Together with his co-workers from ICL and the London School of Hygiene & Tropical Medicine, he established that the distribution of various biomolecules such as lipids and proteins can be visualized in an embryo on different length scales. First, 3D Raman images of entire, several-millimeter-long zebrafish embryos demonstrated Raman imaging of an entire organism. Second, high-resolution Raman imaging revealed microscale features of tissue sections from dorsal muscle, tail and gut. Raman imaging was next used to detect clusters of mycobacterial infection in a zebrafish model for tuberculosis. Based on metabolic differences, Raman spectroscopy could even distinguish between infections arising from different strains. Lastly, time-lapse Raman imaging monitored molecular changes during wound response in living embryos over several hours. The authors expect that, “the ability to perform volumetric and in vivo imaging in unlabeled embryos should provide a host of new opportunities for zebrafish research that can readily complement existing fluorescence imaging techniques.”
The Paper Award SILVER: Chemical characterization of meteorites
From the chemical composition of meteorites, planetary scientists can learn a great deal about their parent bodies’ history. “Studying meteorites and their parent bodies helps us understand how our solar system formed and evolved,” says Mehmet Yesiltas from Kirklareli University, Turkey, winner of the Silver Paper Award 2021. His publication presents a detailed chemical analysis of the Didim meteorite, which he investigated together with his colleagues from research institutions in Turkey, the USA, France and Germany. The Didim meteorite (named after Didim, Turkey, where it fell in 2007) is a chondrite with a relatively rare and varied mineralogical composition, making it especially interesting. The authors investigated its chemical composition on different scales using three spectroscopic methods. Biconical reflectance spectroscopy was used for an initial large-scale assessment and revealed mainly anhydrous silicates. Raman imaging then allowed for a more precise characterization of the rock’s minerals, including feldspars, olivine and pyroxene, and their distributions on the micrometer scale. Also, aromatic hydrocarbons of different thermal metamorphic grades were shown to exist in close proximity within the meteorite. Non-destructive 3D Raman imaging showed that the carbonaceous matter was present beneath an olivine grain inside the meteorite, suggesting its extraterrestrial origin. Furthermore, nano-FTIR spectroscopy indicated that the mineralogical composition of the rock varied even on the sub-micrometer scale.
The Paper Award BRONZE: Thermochemical degradation of ceramic coatings
Jet engines are protected against their extremely high operating temperatures by thermal barrier coatings (TBCs). Ingression of molten calcium, magnesium and alumino-silicates (CMAS) into a TBC during flight causes severe damage to it and shortens the engine’s lifetime. Chance Barrett from the University of Central Florida (UCF), USA, wins the Bronze Paper Award 2021 for presenting 3D Raman imaging as a non-destructive method for analyzing the CMAS-induced degradation of TBCs, together with his co-workers from UCF and the German Aerospace Center. CMAS ingression causes a transition of the TBC to the monoclinic phase. The volume fraction of this phase therefore represents a measure of the degree of degradation and it can be quantified with Raman imaging. 3D Raman maps of TBCs visualized the degradation as a function of depth. The damage was less pronounced in the core of the columns that form the TBC than at their edges, because the gaps between the columns were more accessible. Additionally, time-dependent measurements showed that most of the damage occurred during the first hour of CMAS infiltration. The results were validated by scanning electron microscopy and energy-dispersive X-ray spectroscopy. To the authors’ knowledge, their study is the first to present a non-destructive 3D characterization of TBC degradation at high resolution. They postulate that, “This ability to quantitatively and non-destructively characterize degradation of CMAS infiltrated TBCs will accelerate development of degradation resistant coatings.”
Don’t miss your chance in the WITec Paper Award 2022
WITec invites scientists from all fields of application to participate in the Paper Award 2022 competition (www.witec.de/paper-award). Articles are eligible if they were published in 2021 in a peer-reviewed journal and feature results (at least partially) obtained with a WITec instrument. Submit your work as a PDF to email@example.com before January 31st, 2022. WITec is looking forward to receiving many outstanding publications again.
- Press Release Paper Award 2021 EN (PDF) (732 KB)
- Press Release Paper Award 2021 EN (DOCX) (480 KB)
- Pressemitteilung WITec Paper Award 2021 DE (PDF) (749 KB)
- Pressemitteilung WITec Paper Award 2021 DE (DOCX) (473 KB)
- Picture WITec Paper Award 2021 GOLD (JPG) (1.6 MB)
- Picture WITec Paper Award 2021 SILVER (JPG) (6.6 MB)
- Picture WITec Paper Award 2021 BRONZE (JPG) (1.2 MB)
We're hosting a half-day virtual symposium in cooperation with Spectroscopy Online that will take place on May 19th at 1 p.m. EDT.
This event will feature scientific talks from researchers in academia and industry. Exciting and resonant topics of presentations will include microplastics, 2D materials, human health, biology, geoscience and electrochemistry. The theoretical foundations of Raman imaging will also be covered and the considerations involved in achieving the very highest spectral and spatial resolution will be detailed.
The first session is titled: Raman Imaging and its Potential in Earth & Life Sciences, while the second is: Raman Imaging for Comprehensive Materials Research. Question and answer forums will follow each session.
We cordially invite you to visit the conference page to view the full program and to register:
The cutting edge of Raman-based microparticle characterization gets even sharper
February 1, 2021
WITec GmbH, the pace-setting leader in Raman microscope technology, has enhanced its ParticleScout automated particle analysis tool to offer even greater speed and versatility for finding, classifying and identifying microparticles.
ParticleScout now includes integration time optimization that uses the signal to noise ratio to determine how long each particle is measured for identification. This not only greatly reduces overall measurement time, but also minimizes the effects of fluorescence.
“The first release of ParticleScout was a response to the general demand for a microparticle analysis system built around Raman spectroscopy,” says Harald Fischer, Marketing Director at WITec. “This version is driven by direct feedback from researchers and their specific requirements in laboratories focused on environmental research, food science, pharmaceutics and many other applications.”
The enhanced ParticleScout has added image processing features such as vignetting correction, smart zoom that displays particle information dynamically depending on viewed area, and multiple sample area targeting. These conveniences are complemented by the integration and possible combination of dark-field, bright-field, epifluorescence and transmission sample illumination.
A software routine has been introduced to accelerate measurements of round samples such as filters that contain homogeneously distributed particles. It allows a wedge section to be selected for analysis and the results can then be extrapolated to represent the whole. Another innovation is the smart separation of closely adjacent or touching particles. This is especially useful for densely packed, heterogeneous samples.
Data post-processing with WITec’s TrueMatch™ Raman database management software is updated as well, including the ability to identify individual components in mixed spectra. Hit quality index (HQI) calculation is also optimized with automatic noise reduction and substrate spectra removal. Together these advances enable a new degree of precision in sample characterization.
Finally, the quantitative report that summarizes the results of a ParticleScout investigation can now be formatted with pre-configured templates such as tables, bar graph histograms or pie charts for clear and effective data presentation.
For more on the very latest in automated particle analysis technology, please visit our product page:
- Press Release - Enhanced ParticleScout - English (DOCX) (396 KB)
- Press Release - Enhanced ParticleScout - English (PDF) (229 KB)
- Image - Product Picture - Enhanced ParticleScout (JPEG) (812 KB)
- Graphic - Integration Time Optimization - Enhanced ParticleScout (JPEG) (170 KB)
- Pressemitteilung - Neue ParticleScout Funktionen - Deutsch (PDF) (490 KB)
- Pressemitteilung - Neue ParticleScout Funktionen - Deutsch (DOCX) (223 KB)