[1] P. Ball. Water as an active constituent in cell biology. Chem. Rev., 108, 74-108(2008).

[2] M. Chaplin. Do we underestimate the importance of water in cell biology. Nat. Rev. Mol. Cell Biol., 7, 861-866(2006).

[3] L. Shi et al. Optical imaging of metabolic dynamics in animals. Nat. Commun., 9, 1-17(2018).

[4] E. Alonso‐Ortiz, I. R. Levesque, G. B. Pike. MRI‐based myelin water imaging: a technical review. Magn. Reson. Med., 73, 70-81(2015).

[5] M. Maurer, C. Oostenbrink. Water in protein hydration and ligand recognition. J. Mol. Recognit., 32, e2810(2019).

[6] Z. Xu, L. V. Wang, Q. Zhu. In vivo photoacoustic tomography of mouse cerebral edema induced by cold injury. J. Biomed. Opt., 16, 066020(2011).

[7] R. G. Steen. Edema and tumor perfusion: characterization by quantitative 1H MR imaging. Amer. J. Roentgenol., 158, 259-264(1992).

[8] C.-S. Liao et al. Microsecond scale vibrational spectroscopic imaging by multiplex stimulated Raman scattering microscopy. Light: Sci. Appl., 4, e265(2015).

[9] C. Rao, N. C. Verma, C. K. Nandi. Unveiling the hydrogen bonding network of intracellular water by fluorescence lifetime imaging microscopy. J. Phys. Chem. C, 123, 2673-2677(2019).

[10] K. Kimura et al. Visualizing water molecule distribution by atomic force microscopy. J. Chem. Phys., 132, 194705(2010).

[11] L. V. Wang, J. Yao. A practical guide to photoacoustic tomography in the life sciences. Nat. Methods, 13, 627-638(2016).

[12] J. Yao, L. V. Wang. Photoacoustic microscopy. Laser Photonics Rev., 7, 758-778(2013).

[13] J. Hui et al. Bond-selective photoacoustic imaging by converting molecular vibration into acoustic waves. Photoacoustics, 4, 11-21(2016).

[14] S. Wang et al. Recent advances in photoacoustic imaging for deep-tissue biomedical applications. Theranostics, 6, 2394(2016).

[15] W. Chen, C. Tao, X. Liu. Artifact-free imaging through a bone-like layer by using an ultrasonic-guided photoacoustic microscopy. Opt. Lett., 44, 1273-1276(2019).

[16] Z. Xu, C. Li, L. V. Wang. Photoacoustic tomography of water in phantoms and tissue. J. Biomed. Opt., 15, 036019(2010).

[17] J. Li et al. Time-domain terahertz optoacoustics: manipulable water sensing and dampening. Adv. Photonics, 3, 026003(2021).

[18] J. A. Curcio, C. C. Petty. The near-infrared absorption spectrum of liquid water. JOSA, 41, 302-304(1951).

[19] J.-X. Cheng. New ‘HOPE’ laser for photoacoustic imaging of water. Light: Sci. Appl., 11, 1-2(2022).

[20] P. K. Upputuri, M. Pramanik. Photoacoustic imaging in the second near-infrared window: a review. J. Biomed. Opt., 24, 040901(2019).

[21] L. A. Sordillo et al. Advances in medical applications using SWIR light in the wavelength range from 1000 to 2500 nm. Proc. SPIE, 10873, 108730T(2019).

[22] W. M. Irvine, J. B. Pollack. Infrared optical properties of water and ice spheres. Icarus, 8, 324-360(1968).

[23] J. Swiderski, M. Michalska, G. Maze. Mid-IR supercontinuum generation in a ZBLAN fiber pumped by a gain-switched mode-locked Tm-doped fiber laser and amplifier system. Opt. Express, 21, 7851-7857(2013).

[24] W. Ma et al. 1.9 μm square-wave passively Q-witched mode-locked fiber laser. Opt. Express, 26, 12514-12521(2018).

[25] G. De Valcarcel et al. Transverse patterns in degenerate optical parametric oscillation and degenerate four-wave mixing. Phys. Rev. A, 54, 1609(1996).

[26] G. Wong et al. High-conversion-efficiency widely-tunable all-fiber optical parametric oscillator. Opt. Express, 15, 2947-2952(2007).

[27] C. Li et al. High-power widely tunable all-fiber thulium-assisted optical parametric oscillator at SWIR band. Opt. Lett., 41, 5258-5261(2016).

[28] H.-W. Wang et al. Label-free bond-selective imaging by listening to vibrationally excited molecules. Phys. Rev. Lett., 106, 238106(2011).

[29] R. Cao et al. Multispectral photoacoustic microscopy based on an optical–acoustic objective. Photoacoustics, 3, 55-59(2015).

[30] P. Wang et al. Bond‐selective imaging of deep tissue through the optical window between 1600 and 1850 nm. J. Biophotonics, 5, 25-32(2012).

[31] G. Bi et al. Compact, 2.95-GHz repetition-rate femtosecond optical parametric oscillator with tunable pulse repetition frequency. Opt. Commun., 500, 127339(2021).

[32] H. K. Choi. Long-Wavelength Infrared Semiconductor Lasers(2004).

[33] J. Shi et al. Hybrid optical parametrically-oscillating emitter at 1930 nm for volumetric photoacoustic imaging of water content. eLight, 2, 1-7(2022).

[34] H. Tang et al. A novel fiber optical parametric oscillator for high-contrast and high-speed photoacoustic imaging of water, 1-4(2022).

[35] I. Begleris, P. Horak. Efficiency and intensity noise of an all-fiber optical parametric oscillator. J. Opt. Soc. Amer. B, 36, 551-558(2019).

[36] S. Brosnan, R. Byer. Optical parametric oscillator threshold and linewidth studies. IEEE J. Quantum Electron., 15, 415-431(1979).

[37] M. E. Marhic. Fiber Optical Parametric Amplifiers, Oscillators and Related Devices(2008).

[38] E. Zlobina, S. Kablukov. Fiber optical parametric oscillators. Optoelectron. Instrum. Data Process., 49, 363-382(2013).

[39] G. P. Agrawal. Lightwave Technology: Telecommunication Systems(2005).

[40] N. Englebert et al. Parametrically driven Kerr cavity solitons. Nat. Photonics, 15, 857-861(2021).

[41] H. Høgset et al. In vivo biomolecular imaging of zebrafish embryos using confocal Raman spectroscopy. Nat. Commun., 11, 6172(2020).

[42] M. Hagedorn et al. Water distribution and permeability of zebrafish embryos, Brachydanio rerio. J. Exp. Zool., 278, 356-371(1997).

[43] T. Zhang, D. M. Rawson, G. J. Morris. Cryopreservation of pre-hatch embryos of zebrafish (Brachydanio rerio). Aquatic Living Resour., 6, 145-153(1993).

[44] N. L. Henry, D. F. Hayes. Cancer biomarkers. Mol. Oncol., 6, 140-146(2012).

[45] M.-F. Penet et al. Water and collagen content are high in pancreatic cancer: implications for quantitative metabolic imaging. Front. Oncol., 10, 599204(2021).

[46] J. Fu, H. Wang. Precision diagnosis and treatment of liver cancer in China. Cancer Lett., 412, 283-288(2018).

[47] BB. Lee, S. G. Rockson, S. Rockson, J. Bergan. The diagnosis of edema and its pathogenesis. Lymphedema, 221-228(2018).

[48] R. A. Fishman. Brain edema. New Engl. J. Med., 293, 706-711(1975).

[49] H. K. Kim, S. Y. Namgoong, H. P. Kim. Antiinflammatory activity of flavonoids: mouse-ear edema inhibition. Arch. Pharm. Res., 16, 18-24(1993).

[50] K. Murakami et al. Cold injury in mice: a model to study mechanisms of brain edema and neuronal apoptosis. Progr. Neurobiol., 57, 289-299(1999).

[51] P. Wang et al. Mapping lipid and collagen by multispectral photoacoustic imaging of chemical bond vibration. J. Biomed. Opt., 21, 096010(2012).

[52] L. Li et al. Label-free photoacoustic tomography of whole mouse brain structures ex vivo. Neurophotonics, 3, 035001(2016).

[53] C. Li et al. High-energy all-fiber gain-switched thulium-doped fiber laser for volumetric photoacoustic imaging of lipids. Photonics Res., 8, 160-164(2020).

[54] C. B. Kimmel et al. Stages of embryonic development of the zebrafish. Dev. Dynam., 203, 253-310(1995).

[55] P. Dong et al. HFE promotes mitotic cell division through recruitment of cytokinetic abscission machinery in hepatocellular carcinoma. Oncogene, 41, 4185-4199(2022).

[56] D. Dong et al. Sarsasapogenin-AA13 inhibits LPS-induced inflammatory responses in macrophage cells in vitro and relieves dimethylbenzene-induced ear edema in mice. Acta Pharmacol. Sin., 38, 699-709(2017).

[57] Y. Liu, C. Zhang, L. V. Wang. Effects of light scattering on optical-resolution photoacoustic microscopy. J. Biomed. Opt., 17, 126014(2012).

[58] L. Y. Shi et al. Transmission in near‐infrared optical windows for deep brain imaging. J. Biophotonics, 9, 38-43(2015).

[59] T. Y. Wang, C. Xu. Three-photon neuronal imaging in deep mouse brain. Optica, 7, 947-960(2020).