Raman Gas Analysis with Hollow Core Micro-Structured Optical Fiber Technology

ISI, in collaboration with the Optoelectronics Research Centre (ORC) at the University of Southampton, have developed a flexible on-line gas detection instrument with high specificity and sensitivity that can measure several species simultaneously. This Raman instrument is a first-of-a-kind design utilizing a state-of-the-art hollow core micro-structured optical fiber (HCF), a silica fiber with a tubular hollow core which when filled with the sample gas, facilitates an extended interaction path length between the excitation laser, enhancing gas measurement sensitivity.

This approach also demands very small sample volumes (microliters), and due to its non-destructive nature, the gas sample can be returned to the process post-analysis. For analysis, the sample gas flows into the instrument via a custom designed gas block (Swagelok connection), it then passes through the core of the HCF where the individual molecules interact with the excitation laser, before exiting the instrument via a second gas block. The HCF acts as a lightguide for both the excitation laser and Raman which is detected using a CCD.

Several funded test plans have shown the successful detection of: H2, CO2, CH4, O2 and many more. Additionally, heteronuclear vapor phase organic species and solvents (e.g. acetone and odorless kerosene) have been analyzed via headspace detection. ISI have recently been working within the Fusion sector, on the detection of hydrogen isotopologues within the tritium fuel cycle. Tritium was successfully detected in Q1 of 2025, and a more in-depth test plan is underway.

ISI was awarded a patent in 2023 and continues to develop the technology further. ISI’s current focus is on enhancing the limit of detection (LoD), the current lower LoD is estimated at <2ppm, with no maximum LoD in place.

About the presenter
Jessica Gabb received her master’s degree in chemistry (Hons) in 2015 from Cardiff University, then entered a graduate scheme in the nuclear power sector, working on the lifetime of the existing fleet and chemical analyses. In 2019, she began working within the business development team, supporting the outreach of nuclear technologies into the wider scientific community. Gabb then joined IS-Instruments in April 2021 in the role of business development manager, with a focus on the company’s growth and commercialization.