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How MIX Observation Screening Saves Time for Raman Analysis

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Raman System Section, JASCO Corporation

Comparison of brightfield, darkfield, and MIX observation using a Raman spectrometer on rust on a metal substrate

Figure 1. Difference in appearance depending on observation method (sample: rust on metal substrate)

Since 1958, JASCO Corporation has been in the business of developing and manufacturing optical analysis instruments, as well as providing analytical services. It has adopted some of our microscopy technology for its various Raman spectroscopy products, commonly used for materials analysis.

In a previous blog post, JASCO talked about the advantages of our UIS2 optics and how their infinity-corrected system (rather than finite-corrected) makes it easy to design Raman spectrometers equipped with multiple objective lenses. In this blog post, Takeo Soejima from JASCO Corporation's Raman System Section talks about the implementation of our MIX observation technology into JASCO’s Raman systems and how it helped improve the performance of JASCO’s spectrometers.

Here is the story in Takeo Soejima’s own words:

Clearer Sample Color, Surface Scratches and Defects, and Surface Unevenness

“The MIX observation unit-U-MIXR-2 is a key device for our Raman spectrometers because it can visualize the color of the sample, surface flaws and defects, and surface unevenness more clearly than conventional brightfield observation or darkfield observation. It was in 2018 that we first incorporated the MIX observation unit (the U-MIXR model at the time) into our laser Raman spectrometer NRS-4000/5000 series (Fig. 2) for evaluation. These systems feature automated optical system switching and optical axis adjustment and can be used in a wide range of applications, from analysis of submicron-order minute foreign matter to imaging measurement, through simple software operations.

Figure 1 shows an example where the color of the sample can be seen clearly by using MIX observation. Red is red rust, and black is black rust. Using conventional brightfield, it was difficult to distinguish the color of the particles, and it was necessary to measure all the locations.

JASCO Laser Raman Spectrophotometers

Figure 2. JASCO Laser Raman Spectrometers

MIX Observation: Revealing the Invisible

MIX observation combines brightfield and darkfield illumination methods to achieve a view that leverages the advantages of each. Figure 3 shows the measurement results of another example where only the color-enhanced portions of vitamins were Raman-measured. In Raman measurements, the fluorescence from the sample sometimes interferes with the measurement, so we spent a lot of time investigating the conditions by changing the wavelength of the laser light, which is the light source for Raman measurements. However, MIX observation made it easy to estimate the optimal excitation laser for each sample from the visible color of the sample.

Raman imaging and measurements of vitamins

Figure 3. Example of Raman measurement of vitamins

We are always focusing on expanding the application of Raman spectrometers, and it’s very important to respond quickly to each customer’s request. We previously had a customer approach us with a sample that was difficult to observe cleanly and difficult to position prior to analysis, and we had to take measures to develop a solution in house. Finally, when I tried MIX observation with the MIX slider, it solved the problem wonderfully.

Using conventional darkfield, it was necessary to physically switch the optical system from the brightfield setting, and it was impossible to perform MIX observation. It’s a major advantage that simply inserting this unit into the revolver enables easy darkfield/MIX observation. It also makes it possible to easily select brightfield/darkfield/MIX observation in the software. Using MIX observation, we not only see the sample more clearly, but also the Raman measurement time is greatly reduced.

The Evident MIX observation slider and Olympus objective lens

Figure 4. U-MIXR-2 MIX observation unit

The U-MIXR (Fig. 4) also had the advantage of enabling customers to upgrade their Raman instruments at a low cost, using the revolver from Evident that supports darkfield objectives, so we immediately decided to adopt it. Application examples are also presented on our website as well as our product catalogs, and you can access them here.

Developing the Analyzer Business through Collaboration

Evident has offered us proposals for holding joint events and consulted us on the development of systems for observing and measuring samples more beautifully and quickly. I hope that we will continue to build a strong relationship.”

Thank you to Takeo Soejima for sharing JASCO’s perspective on the advantages of the MIX observation unit for Raman analysis. For more information on integrating our high-quality optical components into your instrument design, visit www.olympus-lifescience.com/oem-components.

For more information on JASCO Corporation, go to https://www.jasco-global.com.

Related Content

OEM Microscope Components for Integration

How UIS2 Optics Have Improved Raman Spectroscopy

Mix Observation Methods to See More in Your Wafer Defect Inspection

Raman System Section, JASCO Corporation

Takeo Soejima began working for JASCO in the Raman spectroscopy application development department, and is now involved in the company’s Raman spectroscopy system development.

September 29, 2023
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