| Title: |
Development and application of a diode laser spectrometer for the measurement of isotope anomalies in carbon dioxide ; Développement et applications d’un spectromètre laser dédié à la mesure des anomalies isotopiques du dioxyde de carbone |
| Authors: |
Stoltmann, Tim |
| Contributors: |
Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ); Université Grenoble Alpes; Samir Kassi; Erik Kerstel |
| Source: |
https://hal.science/tel-02480995 ; Optics [physics.optics]. Université Grenoble Alpes, 2017. English. ⟨NNT : ⟩. |
| Publisher Information: |
CCSD |
| Publication Year: |
2017 |
| Collection: |
Université Grenoble Alpes: HAL |
| Subject Terms: |
carbon dioxide; anomaly; isotope; spectroscopy; ring-down; cavity enhanced; optical feedback; [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics]; [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic |
| Description: |
High-precision molecular absorption spectroscopy has become a widely used tool in physics and metrology. More recently, such techniques have gained some favor in the earth sciences and industrial monitoring, mostly for their compactness and robustness. The determination of isotopic ratios of different isotopic systems is nowadays possible with commercially available laser spectrometers. However, in particular for CO2, the full potential of such techniques for highest precision measurements has yet to be exploited. In this thesis, we present a new spectrometer based on optical feedback frequency locking of a distributed feedback laser (DFB) to a highly stable V-shaped reference cell. In such way, we obtain a near infra-red source reaching sub-kHz frequency resolution with a drift of 30 Hz/s. This ultra-narrow, ultra-stable laser source was then combined with a high-stability, high-finesse ring-down cell, using a robust dither lock scheme. We demonstrated a single-spectrum sensitivity of 1.2 x 10-12 cm-1, obtained in 30 seconds, and reported, for a narrow scan, a record-setting minimum detection level 3.8 x 10-14 cm-1, after less than 10 hours of measurement.We applied this instrument to the measurement of isotopic ratios in CO2 and demonstrated the feasibility of direct measurements of 17O in CO2. 17O is a super-ratio which requires precise measurements of three isotopologues, offering information on the hydrological environment of the past, if measured from carbonate rocks. The instrument yielded a precision of 10 ppm in a record-setting measurement time of 10 minutes, demonstrating that laser spectrometers now perform on the same level as state-of-the-art isotopic ratio mass spectrometers currently used in geoscientific studies. We also demonstrated the rst laser based measurements of the ratio 16O13C18O/13C16O2 ("clumped isotopes"), demonstrating a precision of 20 ppm with a strong potential to go further. The instrument shows the potential to measure all geoscientifically relevant isotopologue ratios in CO2 ... |
| Document Type: |
doctoral or postdoctoral thesis |
| Language: |
English |
| Availability: |
https://hal.science/tel-02480995; https://hal.science/tel-02480995v1/document; https://hal.science/tel-02480995v1/file/Stoltmann_Thesis.pdf |
| Rights: |
info:eu-repo/semantics/OpenAccess |
| Accession Number: |
edsbas.F4855446 |
| Database: |
BASE |