Sensitive carbon monoxide detection based on laser absorption spectroscopy with hollow‐core antiresonant fiber

We proposed a near‐infrared gas sensing system based on mode‐locked cavity‐enhanced absorption spectroscopy. A distributed feedback fiber laser (DFB‐FL) with a central wavelength of 1550 nm was employed as the light source, coupling with a Fabry–Perot (F‐P) cavity with an effective optical path length of 42.7 m served as the gas cell. By utilizing a homemade mode‐locked electric circuit and Pound–Drever–Hall (PDH) technique, the mode‐locking between the DFB‐FL and F‐P cavity was achieved with long‐term fluctuation of 3.2%. System performance was verified using ammonia as the analyte gas with a target line at 1550.17 nm. Allan variance analysis revealed that the minimum detection limit was 15.8 ppm with an averaging time of 216 s, corresponding to an absorption coefficient of 2.3 × 10−7 cm−1.

Section: Introductionmentioning

confidence: 99%

Near infrared ammonia sensing system based on on‐axis cavity‐enhanced absorption spectroscopy using board‐level mode‐locked circuit

Zhu,

Guan,

et al. 2024

“…Different spectroscopy techniques play an important role in the field of sensing. [1][2][3][4][5][6][7][8][9][10][11] Laser absorption spectroscopy, based on Lambert-Beer law, provides information about the type and concentration of gases by measuring the wavelength and intensity of absorption lines. 12 This detection method is less affected by cross-sensitivity among gas components compared to nonoptical methods.…”

Section: Introductionmentioning

confidence: 99%

Theoretical and experimental investigation of chalcogenide suspended waveguide gas sensor

Huang,

Wang,

et al. 2023

To address the issues of low ratio of evanescent field (γ) and high reflectivity between waveguide cross‐section and gas for the mid‐infrared waveguide sensors, we propose a chalcogenide (ChG) suspended waveguide with Ge28Sb12Se60 as the core layer and silica (SiO2) as the buffer layer. The SiO2 beneath the waveguide core ridge structure is removed to create suspended structure. The waveguide sensing performance is obtained using a 10% methane (CH4) sample. The fabricated waveguide exhibits a γ of 112%, which is a 10% improvement compared to a free‐space optical sensor with the same optical path length. The good agreement between the theoretical and experimental results of γ confirms the reliability of our theoretical investigation approach. The influences of fabrication error, environmental temperature, and pressure on sensing performances are discussed. This work provides theoretical guidance for designing waveguide structures with large γ, contributing to the further enhancement of on‐chip sensor performance.

“…All solid-state pulse lasers have unique advantages: small volume, high energy storage, and long life, which can meet the research and application needs in scientific research, 1 industry, medicine, military, and other fields. [2][3][4][5][6][7] The 2 µm band laser, which is safe for human eyes, is located at the atmospheric window and corresponds to the absorption peak of water. It has extremely important application value in the fields of lidar, laser medical treatment, and so on.…”

Section: Introductionmentioning

confidence: 99%

Development of 2 μm all‐solid‐state pulsed laser using a saturable absorber

Zhao

et al. 2023

The pulse laser using a saturable absorber as a passive device has the advantages of narrow pulse width, high repetition rate, and high pulse energy. Low‐dimensional materials have attracted research interest in recent years due to their excellent saturable absorption properties, ultra‐fast carrier response speed, high damage threshold, and so on. This paper gives a brief review of the state‐of‐the‐at 2 µm solid‐state lasers using saturable absorbers. The output performance of lasers in repetition rate, pulse energy, pulse width, and wavelength are summarized. The paper is expected to provide a development direction of novel materials as saturable absorbers in 2 µm solid‐state lasers.