Third derivative frequency stabilization to acetylene saturated absorption in a hollow-core photonic crystal fiber
| Autor: | Liang-Yu Wei, 魏良育 |
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| Rok vydání: | 2014 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 102 Previously, we used a hollow-core photonic crystal fiber as the absorption cell to observe the first derivative signal of P(9) line of the acetylene υ1 + υ3 overtone band. Optical heterodyne method was used in saturation absorption signal detection. The optical heterodyne light source was generated by acousto-optic modulator (AOM). The frequency fluctuation is 97.7 kHz. Due to significant Doppler background, the lock point may have a offset from the center frequency. In this paper, we apply third harmonic derivative signal to make the Doppler backgrounds negligible. The laser frequency can be locked to the line center accurately. The average width of third derivative signal is 30.4 MHz. The average slope is -10.58 V/MHz. The average frequency fluctuation is 68.0 kHz, which is corresponding to a average frequency stability of 3.47 × 10-10 in 100 s. In the experiment of offset frequency lock, if we change the length of delay line that we can get interference signal of different period. We can obtain a interference signal of center frequency of 110.375 MHz when the length of delay line is 2.324 m. Finally, we use an offset frequency lock system to verify that the difference between saturated absorption spectroscopy of ECDL 1 and directly absorption spectroscopy of ECDL 1 is 110 MHz. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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