New laser technique measures hydrogen chemistry in real-world conditions
Researchers have developed a laser spectroscopy method that works through thick windows to analyze hydrogen in flames and enclosed spaces—a breakthrough for monitoring hydrogen fuel quality and safety. The technique could accelerate hydrogen's adoption as a commercial fuel by enabling faster, more reliable quality control in production and storage environments.
Originaltitel: Coherent Raman spectroscopy on hydrogen with <em>in-situ</em> generation, <em>in-situ</em> use, and <em>in-situ</em> referencing of the ultrabroadband excitation
<p>Time-resolved spectroscopy can provide valuable insights in hydrogen chemistry, with applications ranging from fundamental physics to the use of hydrogen as a commercial fuel. This work represents the first-ever demonstration of in-situ femtosecond laser-induced filamentation to generate a compressed supercontinuum behind a thick optical window, and its in-situ use to perform femtosecond/picosecond coherent Raman spectroscopy (CRS) on molecular hydrogen (H<sub>2</sub>). The ultrabroadband coherent excitation of Raman active molecules in measurement scenarios within an enclosed space has been hindered thus far by the window material imparting temporal stretch to the pulse. We overcome this challenge and present the simultaneous single-shot detection of the rotational H<sub>2</sub> and the non-resonant CRS spectra in a laminar H2/air diffusion flame. Implementing an in-situ referencing protocol, the non-resonant spectrum measures the spectral phase of the supercontinuum pulse and maps the efficiency of the ultrabroadband coherent excitation achieved behind the window. This approach provides a straightforward path for the implementation of ultrabroadband H<sub>2</sub> CRS in enclosed environment such as next-generation hydrogen combustors and reforming reactors.</p>