Mid-infrared (mid-IR) and Raman techniques are complementary vibrational spectroscopy methods utilized extensively in Process Analytical Technology (PAT). While both probe molecular vibrations, they rely on fundamentally different optical effects: mid-IR ATR detects the absorption of mid-IR radiation, whereas Raman relies on the inelastic scattering of visible or near-infrared (NIR) laser light.

For system integration in continuous manufacturing or batch processing, selecting the correct fiber-optic probe requires evaluating the chemical matrix, physical media constraints, and target molecular species.

Mid-IR ATR Spectroscopy: Ideal for Polar Bonds Detection

Mid-IR absorption requires a fundamental vibration that induces a change in the molecule's dipole moment. Consequently, mid-IR ATR yields high analytical sensitivity for polar bonds, producing strong, well-resolved absorption bands for functional groups such as C=O, O-H, N-H, and C-O.

In a fiber-optic Attenuated Total Reflection (ATR) probe, radiation propagates through specialty optical fibers to an ATR crystal in direct contact with the reaction medium. Internal reflection within the crystal generates an evanescent field that decays exponentially, limiting the penetration depth to approximately 0.5 - 2 µm into the sample.

Technical Parameters & System Integration:

• Media Compatibility: Because the measurement is confined to the immediate 0.5 - 2 µm contact layer, the technique is robust in turbid, highly scattering, bubbly, or particle-laden media. Optical contact with the crystal must be maintained.
• Reaction Tracking: Mid-IR effectively tracks functional-group chemistry in real time, yielding direct kinetic data for esterification, hydrolysis, oxidation/reduction, amide/peptide formation, and polymerization.
• Water Interference: Aqueous matrices present heavy absorbance interference, though the inherently short pathlength of the ATR crystal makes measurement in aqueous media practical.
• Transmission Limits: Fiber attenuation limits cable lengths to 2-3 m when utilizing standard FTIR spectrometers. Lengths can be extended up to 10 m when integrated with high-power quantum cascade laser (QCL) sources or dual-comb spectrometers.
• Spectral Range: Configurations capture the fingerprint region (600-3100 cm⁻¹) as well as high-wavenumber regions (1550-9000 cm⁻¹), depending on the specific ATR crystal and fiber material.

Raman Spectroscopy: Molecule Polarizability

Raman spectroscopy characterizes vibrational levels through inelastic scattering. A monochromatic laser (typically 532 nm, 785 nm, or 1064 nm) irradiates the sample, and scattered photons undergo a detectable energy shift (the Raman shift) corresponding to a vibrational frequency. A vibration is Raman-active only if it alters the molecule's polarizability.

This fundamental difference means symmetric and non-polar bonds - such as C=C, S-S, and aromatic rings - that are weak or silent in mid-IR yield sharp, high-intensity Raman peaks.

Technical Parameters & System Integration:

• Aqueous Media: Raman's primary advantage in process monitoring is its exceptionally weak water scattering cross-section, making it the superior architecture for monitoring aqueous solutions.
• Signal Optimization & Wavelength Dependency: The Raman scattering cross-section scales as λ/4. Excitation at 532 nm yields higher signal strength and spatial resolution but heavily increases fluorescence interference. Shifting to 785 nm or 1064 nm suppresses background fluorescence at the expense of absolute signal intensity.
• Optical Constraints: Probe length is strictly limited by free-space beam divergence; for a standard 12 mm outer diameter probe, lengths exceeding 200-300 cm are optically challenging.
• Fiber Transmission: Because the signals exist in the visible/NIR spectrum, low-loss silica fibers can be utilized, allowing for cable lengths spanning tens of meters from probe to spectrometer.
• Spectral Range: Standard fiber-optic Raman probes cover 130-4000 cm⁻¹, with specialized configurations achieving measurements down to 25 cm⁻¹ (THz Raman) - accessing low-frequency modes that mid-IR fiber systems physically cannot reach.
• Sample Limitations: The focused laser introduces thermal risks, potentially causing photodegradation or burning in dark, highly absorbing samples. Scattering losses from bubbles or suspended particles also constrain the signal-to-noise ratio.

Complementary Solution Architecture

Mid-IR ATR and Raman fiber-optic spectroscopies operate as complementary, not competing, techniques. Deploying both ATR and Raman probes in parallel within a unified process analytical framework ensures that polar, non-polar, aqueous, and solid-phase parameters are captured entirely, preventing the diagnostic blind spots inherent to relying on a single modality.

Learn more about optimizing fiber-optic system architecture for your specific application at artphotonics.com.

You can read more about our Technical Note here.

Every fiber, cable, and probe that leaves our Berlin facility gets put under a microscope. Literally.

Before a product ships, we inspect the fiber end faces for cracks and contamination, check core/clad geometry, and verify transmission against spec. On mid-IR assemblies, that means confirming losses stay within 0.2–0.3 dB/m in the 9–13 µm range — a number that only holds if every step upstream, from fiber draw to final assembly, was done right. It's slow, it's manual, and it's the reason our fibers perform exactly as the datasheet says they will.

Made in Germany, from raw fiber to finished part

That inspection work happens in-house, in Germany, under ISO 9001 — and has for over 25 years. We draw the fiber, build the cables and probes, and test them all under one roof. Nothing gets waved through on the strength of a supplier's word, because there's no external supplier in the chain to take on faith.

Where standard fiber runs out

Our real point of difference is the mid-IR. Beyond roughly 2.5 µm, standard silica fiber stops transmitting altogether. Our patented polycrystalline silver-halide (PIR) fibers carry light out to 18 µm, making them one of the few fiber options that are flexible, non-toxic, and non-hygroscopic at those wavelengths. That's what allows us to cover 200 nm to 18 µm — UV through mid-IR — from a single manufacturer:

• Specialty fibers: silica, chalcogenide, and polycrystalline silver halide
• Custom fiber optic cables and laser delivery assemblies
• Fiber bundles for imaging, illumination, and light delivery
• ATR, transflection, and Raman probes for in-line process control

Built for where the measurement actually happens

Our probes are designed for the harder end of the job — reactors, pipelines, and aggressive chemistry — for applications where it makes more sense to bring the spectrometer to the sample than the sample to the lab. That's why they're widely used in biopharma, chemical and petrochemical processing, and environmental monitoring, wherever real-time, in-line analysis has to hold up under demanding process conditions.

If you're working on a mid-IR measurement that standard silica can't handle, that's exactly the problem we specialize in solving. Get in touch, or browse our product range to see what's possible.

Whether you are looking for a reliable, cost-effective way to upgrade your laboratory setup or run proof-of-concept testing, the art photonics GmbH Summer Sale provides an excellent opportunity to acquire premium optical equipment.

At art photonics GmbH, our core strength lies in designing and manufacturing highly specialized, industrial-grade wide spectra fiber solutions. We span the spectrum from the UV to the Mid-IR, ensuring continuous fiber throughput, precise real-time process control, and high-fidelity spectroscopy data in environments where standard solutions often fall short.

Right now, we are offering a unique opportunity to evaluate our robust technology at significantly reduced prices. Our seasonal stock inventory includes a variety of high-performance components—ranging from standard laboratory models to specialty demo units—perfectly suited for bench research, method development, and educational applications.

What is on Sale?

• Fiber Probes: Ideal for a wide range of UV to Mid-IR spectroscopy needs. Review the list of available Fiber Optic ATR Probes
• Mid-IR Fiber Cables: Engineered for excellent transmittance in the critical 3–17 µm range. Review the list of available Polycrystalline IR Fiber Cables

Why Take Advantage of This Offer?

• Risk-Free Testing: This is a budget-friendly way to evaluate premium optical technology directly within your specific application.
• Broad Compatibility: We have probes available for ATR, Transflection, Reflection, and Raman configurations across a wide spectral range.
• Ready to Ship: All listed items are available immediately from local stock, while supplies last.

Secure Your Equipment

Quantities for these discounted components are highly limited. To receive a quote or any additional technical information, please reach out directly to sales@artphotonics.com.

In the demanding fields of bio-pharma and advanced R&D, real-time data is essential. Traditionally, securing comprehensive analytical data meant physically switching between different spectroscopic setups, such as ATR, NIR, and Raman. This fragmented approach not only slows down critical processes but also introduces a higher risk of sampling errors.

Why run three separate analyses when you can accomplish it all in real-time with a single probe?

At art photonics GmbH, we engineered our FlexiSpec Combi Fiber Optic Probes to eliminate these process bottlenecks. Our goal is to bring the analytical precision of the laboratory directly into your process line. Whether you are dealing with powders, liquids, or biological tissues, multi-modal analysis is now seamlessly integrated into one robust tool.

Our Combi Probe Lineup

We offer a range of specialized probes designed to meet specific industry challenges:

• ATR + Fluorescence: Designed as a highly cost-effective laboratory solution, this probe combines two to three modalities. It is specifically optimized for accurately differentiating between various biological tissues.
• NIRaman: Built expressly for bio-pharma applications. Engineered with a heated shaft to prevent condensation and featuring exceptionally low straylight (under 1%), it serves as the ultimate tool for the in-line determination of blend potency in powders.
• ATR + NIR + Raman: Our most comprehensive offering. This heavy-duty immersion probe for liquids features three distinct channels (ATR-FTIR, NIR Transflex, and Raman) to provide a complete analytical picture for complex bio-pharma applications.

Elevate Your Process Control

There is no longer a need to compromise on your spectroscopic data or slow down your workflow for multiple sampling stages. By consolidating your analytical methods, you can save time, reduce potential errors, and improve overall process control.

Contact our team today to discuss which combi probe will best upgrade your current laboratory or manufacturing setup.

*** A special note regarding our NIRaman probe: This patented technology was proudly co-developed in partnership with Measure Analyse Control BV and Tomas Vermeire.

Real-time, in-line powder identification usually means a trade-off between speed and accuracy. We proved it doesn't have to.

We recently teamed up with our Nynomic Group partner, m-u-t GmbH, to release a joint Application Note. The goal was simple: build a compact, field-ready NIR setup capable of analyzing complex organics directly in the bulk material, without pulling samples.

Here is the exact hardware stack we used to make it happen:

• NIR Diffuse-Reflection Fiber Probe: Because industrial process lines are brutal, our AP12353 probe features a 12 mm Hastelloy C22 shaft and a rugged sapphire window.
• Optimized Optical Design: A 19-to-1 fiber arrangement specifically designed to keep stray light to an absolute minimum, ensuring you get a clean, reliable optical signal.
• The Spectrometer: m-u-t’s ultra-compact NIRONE S2.0 Fabry-Pérot spectrometer, covering the 1550-1950 nm wavelength range.
• The Light Source: A broadband tungsten-halogen lamp provided by Thorlabs.

The spectral data from materials like soy protein, lactose, and acetylsalicylic acid was so clean and reproducible that we tied the classification model directly to a smartphone app for real-time readouts.

You can read the full Application Note and check out the PCA scores via the link:

Identification of Powders by m-u-t Spectrometer and art photonics Probe

Even better, come talk hardware with us next week at Analytica 2026. We are sharing a booth with m-u-t GmbH and our sister company Avantes, so you can connect with multiple Nynomic Group experts in one place.

• Where: Messe München | Munich, Germany
• When: 24 – 27 March 2026
• Find us at: Booth A3.401

Today, we celebrate International Women's Day by recognizing the brilliance, innovation, and courage of women who continually push the boundaries of science.

The field of photonics is built upon deeply impressive contributions from female scientists. From Maria Goeppert Mayer laying the foundational work for multiphoton absorption to Donna Strickland's Nobel Prize-winning breakthroughs in laser technology, these minds serve as a constant reminder of the power of scientific excellence.

At art photonics GmbH, this same commitment, curiosity, and courage drive our daily work. As we tackle demanding technological challenges, we recognize that true innovation fundamentally relies on diversity, a wealth of perspectives, and equal opportunities. Our success is built on a team that values intelligence, forward-thinking, and the courage to break new ground.

This focus on collaboration and team spirit brings us to a double celebration today. In addition to marking International Women's Day, we are also wishing a very Happy Birthday to our colleague, Albert Sandt. It is a wonderful opportunity to recognize both the global impact of women in our industry and the individuals who make our own workplace so strong.

Here is to celebrating great minds and breaking new ground together.

The optimal choice of a spectral reference is important for building accurate calibration models. In our latest publication of Application Notes, art photonics explores the practical differences between using air and water as references in the quantitative analysis of liquid solutions.

NIR-spectroscopy is widely used for quantitative analysis of solid and liquid samples. When measuring liquid solutions in transmission or transflection geometry using a fiber optic probe, air and water (or another solvent) are the two commonly used reference samples. Both substances are widely available and reproducible in terms of their spectral properties.

To determine how each reference impacts calibration models, we conducted an experimental study using a designed set of 25 samples of a ternary aqueous mixture of ethanol and methanol. Measurements were performed in the 930-1720 nm range using an art photonics Transflection Fiber Probe coupled with a Broadcom Qneo spectrometer.

Key Findings from the Study

• The Air Reference Workflow: Air can be preferred as a reference for its experimental simplicity. However, raw spectra are dominated by the strong signal of water. To build reliable partial least-squares (PLS) regression models, the data typically requires preprocessing - such as first or second derivatives by the Savitzky-Golay algorithm - to emphasize the vibration overtones of the alcohols.
  
• The Water Reference Workflow: When water is used as a reference sample, the resulting spectra tend to be strongly distorted due to the presence of negative peaks (in place of the water signals). Although this makes the spectra less interpretable, their information content remains high, and their suitability for quantitative analysis is not impaired.
  
• Impact on Data Analysis: Using the water sample spectrum as a reference measurement enables accurate prediction of the two alcohols under study without data preprocessing and with a lower number of latent variables. This results in a simpler, and hence, more reliable calibration model.

Conclusion

Both air and water can be successfully used for reference analysis in the analysis of aqueous solutions. While air offers experimental simplicity, using water as a reference simplifies data analysis by avoiding the spectral preprocessing step, which is required for air-based measurements.

Read the full methodology, view the raw and preprocessed spectra, and analyze the cross-validation statistics.

In the high-stakes environment of complex chemical processing, the ability to distinguish and quantify components like ethanol and methanol in real-time is often the deciding factor between a strictly controlled reaction and an off-spec batch.

Traditionally, operators have relied on manual extraction for laboratory analysis. However, this method introduces significant delays and safety risks that modern industry can no longer afford. When you are reacting to problems identified in a lab report hours later, you are not preventing them—you are merely managing the damage.

The Solution: Mid-IR Spectroscopy with Fiber Optic ATR Probes

How do you achieve laboratory-grade precision directly within the process line, without ever extracting a sample?

One of the most effective solutions lies in Mid-IR spectroscopy, utilizing advanced Fiber Optic ATR (Attenuated Total Reflection) Probes. By leveraging Art Photonics’ proprietary Polycrystalline Infrared (PIR) and Chalcogenide Infrared (CIR) fibers, these probes extend the reach of Mid-Infrared spectroscopy directly into the reaction vessel or flow line.

Key Advantages for Industrial Application

Implementing this technology facilitates a shift from reactive analysis to proactive process control:

• Remote Sensing: Measurements are performed remotely from the spectrometer. This keeps sensitive (and expensive) analytical equipment safe, even while the probe is immersed in aggressive chemical environments.
• Sampling-Free Analysis: By measuring directly in the line, you eliminate the need for manual sample extraction. This ensures a continuous, automated data flow and significantly reduces operator exposure to hazardous chemicals.
• Real-Time Process Control: Operators receive immediate feedback on component concentrations. This allows for instant adjustments to process parameters to maintain product integrity and consistency.

Featured Application: Ethanol & Methanol Analysis

Our latest application note details the performance of these MIR ATR probes in the simultaneous analysis of ethanol and methanol mixtures. The study demonstrates that despite the chemical similarities between these alcohols, Art Photonics’ PIR and CIR probes provide robust, highly accurate differentiation.

The resulting data confirms that this method delivers the precision required for demanding industrial applications, making it a viable replacement for traditional offline chromatography.

Is your process ready for the shift to continuous in-line monitoring?

To learn more about the technical specifications and to see the data firsthand, we invite you to read the full documentation.

Moving Beyond the Bench: In-Line FTIR Monitoring with ATR Probes

For decades, Attenuated Total Reflection (ATR) has been a standard technique for FTIR spectroscopy. However, most users are restricted to standard ATR inserts or benchtop accessories. While effective for static lab samples, these setups introduce a critical bottleneck: the sample must be extracted from the reactor and brought to the instrument.

At art photonics, we eliminate this limitation. We enable you to measure ATR spectra directly inside your solution.

The Difference Between ATR Inserts and ATR Probes

Standard inserts require a controlled laboratory environment. In contrast, art photonics ATR Probes are flexible, fiber-optic-based devices designed to bridge the gap between your spectrometer and your process line.

By immersing the probe tip directly into the reaction vessel or flow line, you achieve:

• Real-Time Kinetics: Monitor reaction progress as it happens, without the time lag of sampling loops.
• Process Safety: Eliminate the risk of handling hazardous or toxic samples manually.
• Closed-Loop Control: Feed spectral data directly into your process control system (PAT) for immediate adjustments.

Engineered for Harsh Environments

A common misconception is that fiber optic probes are fragile. Our ATR probes are engineered specifically for industrial robustness. Unlike standard inserts, our probes are built to withstand:

• High Temperatures: Operable in extreme thermal conditions typical of chemical synthesis.
• High Pressures: Designed for high-pressure reactors and flow cells.
• Chemically Aggressive Media: Shaft materials and sealing technologies selected to resist corrosion in harsh solvents.

Watch: Real-Time Monitoring in Action

To demonstrate the capability of in-line measurement, we connected our ATR Probe to a portable FTIR spectrophotometer. In the video below, you can see the dissolution kinetics of sugar in water measured in real-time. This simple setup mirrors complex industrial crystallization or dissolution processes.

Frequently Asked Questions

What is an ATR Probe?
An ATR Probe is a fiber-optic sensor that allows for the in-situ measurement of FTIR spectra by bringing the infrared light to the sample, rather than the sample to the instrument.

Can art photonics probes handle high pressure?
Yes. Our probes are designed for harsh environments, including increased pressures and temperatures found in industrial chemical processes.

Is it possible to measure FTIR spectra in solution without sampling?
Yes. Using an in-line ATR probe allows for direct immersion in the solution, enabling continuous, real-time monitoring without extraction.

Conclusion

Don't let sampling delays compromise your data. Explore how art photonics technology can bring your analytics directly into the process stream.

If you look closely at our holiday card this year, you might notice a familiar tool in an unfamiliar setting. Yes, that is one of our probes in the wine glass! It is a little nod to who we are: even when we are celebrating, we never stop thinking about the science that brings us together.

As we get ready to close the door on 2025, we wanted to send a personal note of thanks. This past year has been filled with exciting developments, but the highlight—as always—has been the people we work with.

Thank you for trusting us with your challenges and for the wonderful collaboration. Whether we were solving complex problems or brainstorming new ideas, working with you has made this year truly memorable.

We are heading into 2026 with a lot of optimism. We are ready to recharge over the break and come back fresh, eager to embrace new opportunities and start exciting new projects with you.

Enjoy the festive season, relax, and here is to a healthy, happy New Year!

Warmest wishes,

The art photonics Team