Photothermal spectroscopy

Detection of trace gases and detection of residual absorbtion

Highly sensitive laser-based spectroscopy methods are primarily used for analytical tasks when it comes to detecting low trace gas concentrations or residual absorption in optical materials. Photothermal common-path interferometry (PCI) uses the secondary effect of the refractive index change resulting from the absorption-induced heating of a material. The absorbed radiation of a powerful pump laser in the material produces a change in the refractive index (»thermal lens«). A second, weak probe laser crosses the beam of the pump laser. The thermal lens causes a modification in the wavefront of the probe laser. Using a lock-in method, this can be measured very sensitively and the strength of the absorption can be determined.

© Fraunhofer IPM
Schematic structure of the PCI spectrometer

Applications »Photothermal spectroscopy«

Quality inspection of high-performance laser optics

Among other applications, Fraunhofer IPM uses photothermal spectroscopy to detect residual absorption in high-performance laser optics.


Detection of trace gases

In the framework of the »ISLAS« project, Fraunhofer IPM is researching possible applications of photothermal spectroscopy for the highly sensitive detection of trace gases.

Publications »Photothermal Spectroscopy«

Publication Type
2023 Breath-Resolved Monitoring of Metabolic Trace Gases with Photothermal Spectroscopy
Wolf, Sebastian; Lindner, Chiara; Trendle, Tobias; Kießling, Jens; Wöllenstein, Jürgen; Kühnemann, Frank
Conference Paper
2023 Time-resolved photothermal breath analysis
Wolf, Sebastian; Lindner, Chiara; Trendle, Tobias; Kießling, Jens; Kühnemann, Frank
Conference Paper
2021 Entwicklung von Faraday-Rotatoren mit stark verbesserten Eigenschaften auf der Grundlage von Kalium-Terbium-Fluorid (KTb3F10) und anderen innovativen Materialien (IsoNova). Schlussbericht
Kühnemann, Frank; Trendle, Tobias
2020 Photothermal Common-Path Interferometry for Trace Gas Detection
Wolf, Sebastian; Trendle, Tobias; Catalan, Norman; Kießling, Jens; Wöllenstein, Jürgen; Kühnemann, Frank
2018 VIS-to-NIR absorption spectroscopy of magneto-optical materials for high-power laser applications
Trendle, Tobias; Kießling, Jens; Kunz, Jachin; Kühnemann, Frank
2017 Measuring residual absorption in highly transparent optical materials using tunable sources. On calibration, spectroscopy and cross-validation
Kühnemann, Frank; Leidinger, Markus; Kießling, Jens; Breunig, Ingo; Fieberg, Stephan; Waasem, Niklas; Buse, Karsten
Diese Liste ist ein Auszug aus der Publikationsplattform Fraunhofer-Publica

This list has been generated from the publication platform Fraunhofer-Publica