Photonics Research, 2019, 7 (8): 08000883, Published Online: Jul. 23, 2019
Adaptive cavity-enhanced dual-comb spectroscopy Download: 704次
Figures & Tables
Fig. 1. Adjustment of f rep and f ceo . Cavity filtering on comb when (a) f rep < FSR and when (b) f rep > FSR . CC, current filtering center; NC, next filtering center. Cavity transmission when (c) f rep is not appropriate, (d) f rep is appropriate and (e) both f rep and f ceo are appropriate.
Fig. 2. Experimental setup. (a) Measurement part; (b) acquisition part. ECDL, external cavity diode laser; CW1, CW2, continuous-wave lasers; PDH, Pound–Drever-Hall detection; EOM, electro-optical modulator; CPL, coupler; PBS, polarization beam splitter; L, lens; PZT, piezo actuator; DCS, dual-comb spectroscopy; Q, quarter-wave plate; H, half-wave plate; blue lines, optical fibers; red lines, spatial beams.
Fig. 3. Optimization of f rep and f ceo and coupled spectrum. Cavity transmission in the experiment when (a) f rep is not appropriate, (b) f rep is appropriate, and (c) f rep and f ceo are appropriate. The nonuniform intervals between adjacent two peaks appearing in (b) and (c) were due to the nonlinearity of the piezo movement. (d) Cavity finesse and corresponding frequency detuning of FSR. (e) The spectra of the original comb and the transmitted light in cases of (a), (c), and fine-tuning of f ceo .
Fig. 4. Spectral measurement of ACE-DCS system. (a) The spectrum of N 2 O sample around 6450 cm − 1 ; blue lines, the measured spectrum after Fourier transforming the IGM, exhibiting each individual comb mode; red lines, the fitted spectrum using the highest points of each comb mode, revealing clear absorption features. (b), (c), and (d) Mode-resolved spectrum in different scales, spanning 14 cm − 1 , 0.23 cm − 1 , and 0.005 cm − 1 , respectively. (e) Transmittance and phase around 6370 cm − 1 ; (f) transmittance of the P(16) line of the (5000 → 0000 ) band and the Voigt fitted result and the line profile provided by HITRAN 2016.
Weipeng Zhang, Xinyi Chen, Xuejian Wu, Yan Li, Haoyun Wei. Adaptive cavity-enhanced dual-comb spectroscopy[J]. Photonics Research, 2019, 7(8): 08000883.