Seminarium Optyczne

Optical frequency combs can serve as a radiation source in spectroscopic measurements, providing high sensitivity, resolution, and speed. The strongest absorption lines of many molecules are in the mid-infrared spectral range (>3 μm). To increase the sensitivity of spectroscopic systems, extending the light-gas interaction path is necessary. Classically, it is realized through multipass cells or optical cavities. However, they have some disadvantages, such as difficulty aligning the light, high losses, or unwanted interference. An alternative approach is to use the so-called antiresonant hollow-core fibers (ARHCF). ARHCFs are characterized by a wide, low-loss transmission range in the mid-IR, high quality of the delivered beam, and their air core can be filled with the target gas sample, making them well-suited for laser-based gas sensing. In this presentation, I will discuss the advantages and disadvantages of antiresonant hollow-core fibers, show the possibility of measuring gases in low vacuum, and provide evidence that ARHCFs could be a promising alternative to multipass cells.