Application laboratory infrared lasers

The QCL has established itself as an ideal laser light source for innovative infrared spectroscopy techniques in the past years. Thanks to its broad spectral tunability in the infrared wavelength range between 4 μm and 12 μm, as well as its high spectral brilliance, the QCL is ideally suited for a wide range of measurement tasks.

Application examples

• Process analysis: Online monitoring of relevant chemical reactions
• Medical diagnostics and therapy: Breath analysis and blood glucose measurements
• Environmental and production metrology: Monitoring of drinking water in waterworks
• Food production: Identification of spoiled or sensory defective food
• Safety and security engineering: Detection of traces of hazardous substances or source materials of explosives

This innovative technology is based on wavelengths in the mid- to long-wave infrared range and identifies chemical substances far more reliably than comparable spectroscopic measurement techniques in the near infrared wavelength range. It facilitates clear identification of various solids and liquids within a few seconds only – culminating in real-time measurements.

The influence of parameters such as temperature and pressure can directly be monitored and optimized for enhanced yield and reduced production time. It is thus possible to develop e. g. new pharmaceutical products faster and at lower costs.

Measurement methods

• Transmission and backscatter spectroscopy
• ATR or microfluidic spectroscopy
• QCL microscopy
• Point-of-interest (POI) spectroscopy

POI scanner

Our point-of-interest system demonstrates inline quality assurance in the pharmaceutical packaging industry. For processes where tablets of different compositions run on the same line, or in patient-specific blister packaging where tablets cannot be clearly distinguished using visible camera-based systems our system complements the information with the IR fingerprint of each tablet. Using machine vision, the system detects the blister package and the position of each tablet inside the blister and records an infrared backscatter spectrum of each. The classification is done based on a neural network. In this way, a 12-tablet blister is inspected in less than 0.3 seconds.

Transportable 1D and 2D IR-Laser Spectrometer

The MOEMS-EC-QCL technology developed at Fraunhofer IAF is characterized not only by its high measurement speed but also by its robustness and small size. This makes it ideally suited for compact portable or handheld systems, where movements inevitably occur and thus the measurement spot shifts. For example, this technology can support forensic crime scene investigations by enabling on-site personnel to make rapid, non-contact, non-destructive measurements directly on site to identify substances.

In the application laboratory, an IR laser spectroscopy demonstrator for contactless IR laser backscatter spectroscopy of solids is available. The demonstrator has spatial (1D and 2D) scanning capability, allowing for hyperspectral and data-fused visualizations of a scene to be created.

Multicore laser systems

The strength of MOEMS EC QCLs is the spectral measurement speed of one kilohertz. However, the spectral coverage is limited compared to FTIR spectroscopy. To increase the spectral coverage, Fraunhofer IAF's laser technology enables multiplexing—a process in which several spectrally complementary modules are coupled together. This increases the spectral coverage without reducing the measurement speed. Compared to competing approaches, the resulting multicore systems are very compact. Such multicore systems are available for demonstrations in the application laboratory.