Open AccessOffset-frequency locking of extended-cavity diode lasers for precision spectroscopy of water at 138~$\mu$m
Author(s) -
L. Gianfrani,
Antonio Castrillo,
Eugenio Fasci,
G. Galzerano,
Giovanni Della Casa,
P. Laporta
Publication year - 2010
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.021851
Subject(s) - laser , optics , spectrometer , materials science , tunable diode laser absorption spectroscopy , spectroscopy , offset (computer science) , diode , tunable laser , reproducibility , frequency offset , semiconductor laser theory , optoelectronics , physics , chemistry , telecommunications , channel (broadcasting) , chromatography , quantum mechanics , computer science , orthogonal frequency division multiplexing , programming language
We describe a continuous-wave diode laser spectrometer for water-vapour precision spectroscopy at 1.38 μm. The spectrometer is based upon the use of a simple scheme for offset-frequency locking of a pair of extended-cavity diode lasers that allows to achieve unprecedented accuracy and reproducibility levels in measuring molecular absorption. When locked to the master laser with an offset frequency of 1.5 GHz, the slave laser exhibits residual frequency fluctuations of 1 kHz over a time interval of 25 minutes, for a 1-s integration time. The slave laser could be continuously tuned up to 3 GHz, the scan showing relative deviations from linearity below the 10{-6} level. Simultaneously, a capture range of the order of 1 GHz was obtained. Quantitative spectroscopy was also demonstrated by accurately determining relevant spectroscopic parameters for the 22,1→22,0line of the H2(18)O v1+v3 band at 1384.6008 nm.