Tm3+:ZBLAN fiber lasers and their applications for spectroscopy
Bibliographic record
Abstract
Thulium ions (Tm3+) provide an effective means for developing fiber lasers at a wide range of wavelengths. Additionally, the extended transmission window of ZBLAN glass allows for operation well into the mid-infrared range. This thesis presents the design of several single and multi-wavelength Tm3+:ZBLAN fiber lasers.First, an optimized laser cavity operating around 1480 nm is designed by measuring several different cavity configurations and lengths of gain fiber. Using a 34 cm length of gain fiber and a 4% Fresnel air reflection as the output mirror/coupler, 32% conversion efficiency is obtained, with a threshold pump power of 400 mW and a maximum output power around 400 mW.Next, a dual-band Tm3+:ZBLAN fiber laser is designed, emitting simultaneously around 810 nm through the 3H4 ï 3H6 transition and around 1480 nm through the 3H4 ï 3F4 transition. This is the first demonstration of a fiber laser which uses the same piece of gain fiber for two different transitions which share the same upper energy level (3H4 in this case). Simultaneous emission at both laser wavelengths with 20% slope efficiencies is obtained.Finally, a three-wavelength Tm3+:ZBLAN fiber laser emitting at 1460/1503/1873 nm is designed using two independent gain branches. Simultaneous operation at all three wavelengths is obtained, with approximately 10 mW output power at each wavelength. The peak fluctuations are stable within 1.5 dB. Wavelength switching through a polarization controller is also demonstrated in the 1460/1503 laser branch. The laser was then used in single-pass absorption measurements for detecting water in acetone. Molar absoprtivities within 10-20% of the theoretical values are obtained from the absorption measured at each individual wavelength.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".