[1] A O’Keefe, DAG Deacon. Cavity ring-down optical spectrometer for absorption measurements using pulsed laser sources. Rev Sci Instrum, 59, 2544-2551(1988).

[2] D Romanini, AA Kachanov, N Sadeghi et al. CW cavity ring down spectroscopy. Chem Phys Lett, 264, 316-322(1997).

[3] G Berden, R Peeters, G Meijer. Cavity ring-down spectroscopy: experimental schemes and applications. Int Rev Phys Chem, 19, 565-607(2000).

[4] GW Truong, KO Douglass, SE Maxwell et al. Frequency-agile, rapid scanning spectroscopy. Nat Photonics, 7, 532-534(2013).

[5] G Giusfredi, S Bartalini, S Borri et al. Saturated-absorption cavity ring-down spectroscopy. Phys Rev Lett, 104, 110801(2010).

[6] G Gagliardi, HP Loock. Cavity-Enhanced Spectroscopy and Sensing(2014).

[7] CS Goldenstein, RM Spearrin, JB Jeffries et al. Infrared laser-absorption sensing for combustion gases. Prog Energy Combust Sci, 60, 132-176(2017).

[8] A Farooq, ABS Alquaity, M Raza et al. Laser sensors for energy systems and process industries: perspectives and directions. Prog Energy Combust Sci, 91, 100997(2022).

[9] Q Chen, L Liang, QL Zheng et al. On-chip readout plasmonic mid-IR gas sensor. Opto-Electron Adv, 3, 190040(2020).

[10] YH Liu, SD Qiao, C Fang et al. A highly sensitive LITES sensor based on a multi-pass cell with dense spot pattern and a novel quartz tuning fork with low frequency. Opto-Electron Adv, 7, 230230(2024).

[11] D Mondelain, S Vasilchenko, P Čermák et al. The self- and foreign-absorption continua of water vapor by cavity ring-down spectroscopy near 2.35 μm. Phys Chem Chem Phys, 17, 17762-17770(2015).

[12] DE Vogler, MW Sigrist. Near-infrared laser based cavity ringdown spectroscopy for applications in petrochemical industry. Appl Phys B, 85, 349-354(2006).

[13] I Galli, S Bartalini, R Ballerini et al. Spectroscopic detection of radiocarbon dioxide at parts-per-quadrillion sensitivity. Optica, 3, 385-388(2016).

[14] AD McCartt, J Jiang. Room-temperature optical detection of 14CO2 below the natural abundance with two-color cavity ring-down spectroscopy. ACS Sens, 7, 3258-3264(2022).

[15] Y Chen, KK Lehmann, J Kessler et al. Measurement of the 13C/12C of atmospheric CH4 using near-infrared (NIR) cavity ring-down spectroscopy. Anal Chem, 85, 11250-11257(2013).

[16] MT Cone, JD Mason, E Figueroa et al. Measuring the absorption coefficient of biological materials using integrating cavity ring-down spectroscopy. Optica, 2, 162-168(2015).

[17] DA Long, AJ Fleisher, Q Liu et al. Ultra-sensitive cavity ring-down spectroscopy in the mid-infrared spectral region. Opt Lett, 41, 1612-1615(2016).

[18] SG Baran, G Hancock, R Peverall et al. Optical feedback cavity enhanced absorption spectroscopy with diode lasers. Analyst, 134, 243-249(2009).

[19] B Argence, B Chanteau, O Lopez et al. Quantum cascade laser frequency stabilization at the sub-Hz level. Nat Photonics, 9, 456-460(2015).

[20] G Zhao, JF Tian, JT Hodges et al. Frequency stabilization of a quantum cascade laser by weak resonant feedback from a Fabry-Perot cavity. Opt Lett, 46, 3057-3060(2021).

[21] J Ohtsubo. Semiconductor Lasers: Stability, Instability and Chaos(2013).

[22] N Schunk, K Petermann. Numerical analysis of the feedback regimes for a single-mode semiconductor laser with external feedback. IEEE J Quantum Electron, 24, 1242-1247(1988).

[23] J Morville, S Kassi, M Chenevier et al. Fast, low-noise, mode-by-mode, cavity-enhanced absorption spectroscopy by diode-laser self-locking. Appl Phys B, 80, 1027-1038(2005).

[24] S Kassi, T Stoltmann, M Casado et al. Lamb dip CRDS of highly saturated transitions of water near 1.4 μm. J Chem Phys, 148, 054201(2018).

[25] J Burkart, D Romanini, S Kassi. Optical feedback frequency stabilized cavity ring-down spectroscopy. Opt Lett, 39, 4695-4698(2014).

[26] G Zhao, DM Bailey, AJ Fleisher et al. Doppler-free two-photon cavity ring-down spectroscopy of a nitrous oxide (N2O) vibrational overtone transition. Phys Rev A, 101, 062509(2020).

[27] V Motto-Ros, J Morville, P Rairoux. Mode-by-mode optical feedback: cavity ringdown spectroscopy. Appl Phys B, 87, 531-538(2007).

[28] A Maity, S Maithani, M Pradhan. Cavity ring-down spectroscopy: recent technological advancements, techniques, and applications. Anal Chem, 93, 388-416(2021).

[29] LA Coldren, SW Corzine, ML Mašanović. Dynamic effects. In Coldren LA, Corzine SW, Mašanović ML. Diode Lasers and Photonic Integrated Circuits(2012).

[30] F Capasso, C Gmachl, DL Sivco et al. Quantum cascade lasers. Phys Today, 55, 34-40(2002).

[31] FP Mezzapesa, LL Columbo, M Brambilla et al. Intrinsic stability of quantum cascade lasers against optical feedback. Opt Express, 21, 13748-13757(2013).

[32] BB Zhao, XG Wang, C Wang. Strong optical feedback stabilized quantum cascade laser. ACS Photonics, 7, 1255-1261(2020).

[33] BJ Orr, YB He. Rapidly swept continuous-wave cavity-ringdown spectroscopy. Chem Phys Lett, 512, 1-20(2011).

[34] GW Truong, LW Perner, DM Bailey et al. Mid-infrared supermirrors with finesse exceeding 400000. Nat Commun, 14, 7846(2023).

[35] XY Li, ZF Fan, Y Deng et al. 30-kHz linewidth interband cascade laser with optical feedback. Appl Phys Lett, 120, 171109(2022).

[36] M Yang, Z Wang, QX Nie et al. Mid-infrared cavity-enhanced absorption sensor for ppb-level N2O detection using an injection-current-modulated quantum cascade laser. Opt Express, 29, 41634-41642(2021).

[37] A Foltynowicz, FM Schmidt, W Ma et al. Noise-immune cavity-enhanced optical heterodyne molecular spectroscopy: Current status and future potential. Appl Phys B, 92, 313-326(2008).

[38] QX Nie, Z Wang, S Borri et al. Mid-infrared swept cavity-enhanced photoacoustic spectroscopy using a quartz tuning fork. Appl Phys Lett, 123, 054102(2023).

[39] W Jin, YC Cao, F Yang et al. Ultra-sensitive all-fibre photothermal spectroscopy with large dynamic range. Nat Commun, 6, 6767(2015).

[40] XY Liao, XG Wang, K Zhou et al. Terahertz quantum cascade laser frequency combs with optical feedback. Opt Express, 30, 35937-35950(2022).

[41] W Guan, ZP Li, SM Wu et al. Relative phase locking of a terahertz laser system configured with a frequency comb and a single-mode laser. Adv Photonics Nexus, 2, 026006(2023).