Today, 21 October, is the Day of Photonics.

The date marks the day in 1983 when the General Conference on Weights and Measures fixed the speed of light at exactly 299,792,458 m/s. The European Photonics Industry Consortium (EPIC) started the Day of Photonics in 2014 to make the field more visible outside labs and companies.

For us at art photonics, it is also a good day to thank the people we work with: researchers, process engineers and laser developers who take our fibers into their reactors, labs and production lines, and who regularly bring us applications that a standard fiber cannot handle.

Our corner of photonics lies beyond the red end of the spectrum. In 1800, William Herschel placed a thermometer just past the red light from a prism and measured a higher temperature than in the visible colours. It was the first evidence of infrared radiation, light that we feel as warmth but cannot see.

More than two centuries later, most of what we make in Berlin exists to bring that light to places where it is otherwise hard to measure or deliver. Our fiber-optic ATR and Raman probes are used for in-line process monitoring, our mid-IR fiber cables guide the beams of quantum cascade lasers, and our fiber delivery systems carry 10.6 µm CO₂ laser radiation. Behind all of them are our specialty fibers: chalcogenide and polycrystalline (PIR) fibers for the mid-infrared, and silica fibers for the UV to NIR range.

Happy Day of Photonics to our customers, partners and everyone working with light, in research and in industry.

Behind every specialty optical fiber we manufacture and ship at art photonics, there is a dedicated team committed to getting every detail exactly right. Today, we are delighted to shine a spotlight on one of the essential people behind our production lines: Nicole, a Production Employee at art photonics.

Recently marking her 5-year work anniversary with us, Nicole has become a cornerstone of our daily operations. Over the past half-decade, she has embodied the core principle that drives our manufacturing process: uncompromising quality.

For Nicole, maintaining high standards is both personally and professionally fulfilling. Reflecting on her time with the company, she shares:

"I enjoy working at art photonics because I can be part of the company's development and actively contribute to its success through the quality of my work. I like the family-like atmosphere, which is why I really enjoy coming to work."

At art photonics, quality is not merely a benchmark on paper; it is a continuous, everyday practice. It is the foundation of the trust our customers have placed in us for decades. Nicole takes particular pride in knowing that the meticulous work she performs directly strengthens and sustains these long-standing client relationships.

Beyond technical excellence, it is the people who make art photonics a truly special place to work. We are a team that grows together, supports one another, and takes immense pride in delivering innovative photonics solutions to the world. The "family-like atmosphere" that Nicole values is something we actively cultivate, ensuring our production floor is a place of both high performance and mutual respect.

We want to extend a huge thank you to Nicole for her unwavering commitment and for being an invaluable part of the art photonics family for the last five years. Here’s to many more!

During active pharmaceutical ingredient (API) crystallization and drying, comprehensive process understanding demands simultaneous insight into chemical composition and solid-state structure. Operators routinely track two distinct parameters in real time: residual solvent or moisture content, and crystal polymorphism.

Historically, monitoring both attributes in situ presented a practical instrumentation bottleneck. Near-infrared (NIR) spectroscopy excels at quantifying water and solvent levels, while Raman spectroscopy provides the molecular fingerprint required to distinguish between polymorphic forms, hydrates, and amorphous phases. Running both techniques concurrently typically required two dedicated immersion probes—demanding multiple reactor ports that are rarely available on benchtop vessels, filter dryers, or pilot equipment.

Synchronous In Situ Acquisition in One Shaft

To solve this physical constraint, art photonics designed the NIRaman Combi Probe. By integrating a NIR diffuse-reflectance channel and a 785 nm Raman optical channel within a single 19 mm diameter shaft, the probe delivers synchronized measurements from the exact same sample volume.

Both channels collect spectral data concurrently without optical cross-talk, operating across powders, crystalline slurries, and liquid phases. Because measurements take place directly inside the process stream, the probe eliminates the need for sample extraction, bypass loops, or manual preparation.

Primary Application Areas

• API Crystallization & Drying: Real-time quantification of solvent removal kinetics via NIR paired with continuous verification of crystal structure and polymorphic purity via Raman.
• Raw Material Verification: Fast chemical identification and solid-state validation of incoming materials in a single measurement cycle.
• Blend Uniformity & Potency: Simultaneous tracking of active ingredient distribution and moisture balance during solid-dose blending.
• Reaction Kinetics & Phase Transitions: Continuous monitoring of reaction progress and intermediate phase formations from laboratory synthesis to commercial production.

From End-Product Testing to Active Process Control

Offline sampling and release testing only identify failures after the batch is completed. Detecting polymorphic shifts, unwanted solvate formations, or over-drying at the moment they occur allows operators to intervene immediately and steer the process within its validated design space.

The NIRaman Combi Probe is available in laboratory and pharma-grade configurations, featuring sanitary process connections and materials designed to meet pharmaceutical manufacturing standards.

The simultaneous quantitative determination of dissolved Cu²⁺, Co²⁺ and Ni²⁺ ions is important in many fields. These include metallurgy, geology, industrial wastewater analysis and the monitoring of biotechnological processes. In many cases, their concentrations need to be measured directly at the sampling site or in-line during an operating process.

The Challenge of Metal Ion Monitoring

Copper, cobalt and nickel are widely used in alloy production, electroplating, battery technologies and other industrial applications. Reliable determination of Cu²⁺, Co²⁺ and Ni²⁺ is important for wastewater monitoring and process control for two primary reasons:

• Environmental Safety: Mining and industrial processing of these metals can generate wastewater containing dissolved metal ions, which must be monitored because elevated concentrations may harm aquatic ecosystems.
• Biotechnological Control: These elements also serve as trace nutrients in selected biotechnological processes.

Although traditional methods such as atomic absorption spectroscopy, inductively coupled plasma techniques, electrochemical analysis and laboratory spectrophotometry can provide high sensitivity and selectivity, they do not always meet the requirements of rapid analysis because they commonly require sampling and sample preparation. For field and process applications, analysis at the sampling site with minimal sample preparation or directly in-line without sampling is therefore desirable.

The Fiber-Optic Spectroscopy Solution

Visible absorption spectroscopy is well suited to the determination of Cu²⁺, Co²⁺ and Ni²⁺ because these ions exhibit characteristic absorption bands in the visible region. Characteristic spectral signatures in the visible region allow their measurement using compact spectrometers and fiber-optic probes.

However, substantial overlap between the absorption bands makes simultaneous determination of the three ions difficult using conventional single-wavelength photometric measurements. Combined with multivariate calibration, this equipment extracts concentration information from the full spectrum and thus enables the analysis of complex mixtures without prior separation.

Figure 1. Measurement setup with a Transflection fiber-optic probe (art photonics GmbH) with an adjustable optical path length.

Methodology and Experimental Setup

In this application note, absorbance spectra of ternary aqueous solutions of copper(II), cobalt(II) and nickel(II) nitrates were measured in the visible and short-wave near-infrared regions using a fiber-optic transflection probe (art photonics GmbH, Germany) and a compact slit-type spectrometer.

• Optical Path Length: Set to 10.0 mm.
• Illumination: Provided by an AvaLight-DH-S halogen light source (Avantes BV, the Netherlands).
• Samples: A calibration set of 27 ternary aqueous solutions (25.0 mL each) was prepared from the hydrated metal nitrates Cu(NO₃)₂·3H₂O, Co(NO₃)₂·6H₂O and Ni(NO₃)₂·6H₂O according to a diagonal experimental design.
• Reference: The reference spectrum was recorded in air without a sample.

Figure 2. Diagonal experimental design for ternary aqueous mixtures of copper(II), cobalt(II) and nickel(II) nitrates [A. Bogomolov, Anal. Chim. Acta 951 (2017) 46-57]. Open and filled circles represent training and validation samples, respectively; labels indicate sample numbers.

Figure 3. Absorbance spectra of the 27 designed copper(II), cobalt(II) and nickel(II) nitrate solutions. The spectra were smoothed using the Savitzky-Golay algorithm. The three replicate spectra for each sample are plotted in the same colour.

Calibration Models

The resulting spectra were analysed, and a partial least squares regression model for multiple response variables (PLS2) was developed to determine the concentrations of all three metal ions from a single spectrum of an unknown mixture.

Five latent variables (LVs) were required to obtain accurate and robust calibration models for all three metal ions:

• Three LVs were associated with variations in metal concentrations.
• Two LVs may be related to weak spectral effects known to arise from metal-nitrate interactions and salt-induced changes in the water absorption band near 970 nm.

Figure 4. Predicted versus reference concentrations for Cu²⁺ (top), Co²⁺ (middle) and Ni²⁺ (bottom) in the validation set obtained with the five-latent-variable PLS2 model.

Results and Conclusion

The proposed method enables simultaneous determination of copper(II), cobalt(II) and nickel(II) from a single spectrum recorded over the 380-1000 nm range. Simultaneous determination was achieved over concentration ranges of up to approximately 0.10 mol/L (100 mmol/L or 0.6% m/v), with prediction errors of approximately 0.3-1.2 mmol/L.

The obtained results point to the possibility of achieving low detection limits for all three analytes. The broad working range and high prediction accuracy make the method suitable for various practical applications. The proposed approach can be implemented as a compact optical system for rapid field analysis and wastewater monitoring, as well as for in-line process analysis in industrial and biotechnological applications.

Read the full text of the Application Note here.

We are happy to welcome Joachim Gerike to the art photonics GmbH team as our new Product Line Manager.

With a Dipl.-Ing. in Mechanical Engineering from Technische Universität Braunschweig and a career in the optical industry dating back to 1996, Joachim brings decades of highly specialized expertise to our operations.

His extensive background covers everything from medical operating microscopes for surgical applications to camera-controlled packaging systems for the pharmaceutical industry, including leadership experience as Head of a Business Unit for medical applications.

At art photonics GmbH, Joachim will act as a bridge connecting our advanced fiber optics solutions to entirely new market segments. His strategic focus will be guiding our innovations from customized R&D projects into scalable, reliable serial production.

Armed with deep knowledge of the medical device industry and sharp sales strategies, friends of him describe his approach perfectly: "Der Möglichmacher" (The one who makes things happen).

Please join us in welcoming Joachim to the team. We are excited for the impact his experience and drive will bring.

When your research or production takes you into extreme environments, maintaining perfect optical transmission should never be a hurdle.

At art photonics GmbH, we invite you to explore our FlexiRay® Vacuum Fiber Optic Feedthroughs - engineered to provide a highly flexible, continuous optical path directly into your vacuum or pressurized chambers.

Whether you are conducting Mid-IR spectroscopy, flexible IR pyrometry, or routing power for Quantum Cascade lasers, our feedthrough assemblies are designed to be the preferred choice for advanced optical engineering.

Here is what makes our solution stand out:

• Continuous Fiber Path (No Intermediate Splices): Say goodbye to the high coupling losses associated with traditional split setups. Our unique single-piece design allows the entire cable to pass directly through the flange without an intermediate repeater. This ensures excellent, uninterrupted signal throughput from the source directly to your sample.
• Exceptionally Low Leak Rate: Reliability is critical in vacuum environments. Our feedthroughs are Helium leak-tested to perform below detection limits (better than 5x10⁻¹² mbar*l/s). The system confidently handles pressures ranging from 10 Bar down to 10⁻⁷ Torr.
• Wide Temperature Tolerance: Built for environmental extremes, these feedthroughs support cryogenic applications operating down to 2K, as well as high-temperature setups reaching up to 600°C when utilizing our specialized Cu-coated silica fibers.
• Mid-IR and Laser Power Delivery: Seamlessly route light and laser power across the entire 0.2 to 18 µm spectrum. Our assemblies are available with Silica, PIR, CIR, and Fluoride glass fibers to perfectly match your specific wavelength requirements.
• Standard KF/CF Flanges & Adjustable Cable Length: Designed for seamless integration, our feedthroughs fit any requested flange type, including standard KF and CF flanges. Furthermore, the movable cable design allows you to adjust the exact length needed inside your chamber for ultimate installation flexibility.

Ready to elevate your optical integration?

Explore the full technical specifications and find the perfect configuration for your next project on our product page: art photonics Vacuum Fiber Optic Feedthroughs

Are you still waiting on offline lab samples when an in-line ATR probe could give you real-time process control?

Transitioning from offline sampling to real-time monitoring remains one of the most significant bottlenecks in Process Analytical Technology (PAT) today. At art photonics GmbH, our FlexiSpec® ATR Probes are engineered to eliminate that delay entirely, bringing the laboratory directly to your production line.

We do not simply build probes; we provide the fiber optic bridge between your spectrometer and your process. By enabling direct, in-situ measurements, we empower engineers to capture crucial spectral data exactly when it matters—in real-time.

Engineered for Harsh Environments

Industrial applications require rugged, uncompromising solutions. Designed to operate under the most demanding conditions, our ATR probes deliver continuous reliability without sacrificing analytical precision.

Key features of the FlexiSpec® lineup include:

• Temperature resistance ranging from -150°C to +250°C
• Pressure tolerance up to 200 Bar (with up to 300 Bar available upon request)
• A specialized "No Dead Zone" design, perfectly optimized for continuous liquid flow
• Complete compatibility with FT-IR, FT-NIR, and any standard benchtop devices

Broad Industry Applications

Whether your facility is tracking volatile solvent composition, monitoring complex polymerizations, or controlling precise biopharma crystallization processes, our in-line probes seamlessly integrate into your workflow to prevent downtime and optimize yield.

Explore the full capabilities of our technology and find the right fit for your facility by reviewing our complete ATR probe lineup.

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.