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The performance of this apparatus was systematically examined through the generation of HHG spectra from 99.7% isopropanol [(CH3)2CHOH], 99.7% ethanol (CH3CH2OH), and liquid water (H2O). A negligible contribution from the gas-phase was verified by a direct comparison between the liquid-phase and gas-phase under an optimal configuration. Under the current experimental conditions, the measured high-order harmonic spectra (HHS) exhibited a distinct maximum photon energy of 20\u00a0eV, with intensity decreasing as the harmonic order increased. Our two-band model based on the semiconductor Bloch equations suggests that HHSs from liquids reach saturation very quickly. Moreover, we measured the time-dependent HHS of liquid isopropanol [(CH3)2CHOH] using a non-collinear 800\u00a0nm pump\u2013probe Mach\u2013Zehnder interferometer. These preliminary results demonstrate the operational capability of liquid-based HHG spectroscopy and highlight its potential for probing ultrafast electron dynamics and molecular properties in liquids.<\/jats:p>","DOI":"10.1063\/5.0278967","type":"journal-article","created":{"date-parts":[[2026,1,28]],"date-time":"2026-01-28T13:39:01Z","timestamp":1769607541000},"update-policy":"https:\/\/doi.org\/10.1063\/aip-crossmark-policy-page","source":"Crossref","is-referenced-by-count":1,"title":["A liquid-phase high-order harmonic generation apparatus for investigating ultrafast dynamics in liquids"],"prefix":"10.1063","volume":"97","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1088-874X","authenticated-orcid":false,"given":"Wenchao","family":"Zhao","sequence":"first","affiliation":[{"name":"Institute of Physics, Chinese Academy of Sciences 1 , Beijing 100190,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-4728-3641","authenticated-orcid":false,"given":"Zepeng","family":"Qian","sequence":"additional","affiliation":[{"name":"School of Optoelectronic Science and Engineering, South China Normal University 2 , Guangzhou 510631,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-0743-2727","authenticated-orcid":false,"given":"Yuanjie","family":"Pan","sequence":"additional","affiliation":[{"name":"Institute of Physics, Chinese Academy of Sciences 1 , Beijing 100190,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-4213-5803","authenticated-orcid":false,"given":"Jinkai","family":"Zhang","sequence":"additional","affiliation":[{"name":"Institute of Theoretical Physics, State Key Laboratory of Quantum Optics and Quantum Optics Devices 3 , Taiyuan 030006,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-0908-7230","authenticated-orcid":false,"given":"Menglong","family":"Zhao","sequence":"additional","affiliation":[{"name":"School of Mechanical and Automotive Engineering, South China University of Technology 4 , Guangzhou 510641,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-4555-6766","authenticated-orcid":false,"given":"Gefei","family":"Li","sequence":"additional","affiliation":[{"name":"Institute of Physics, Chinese Academy of Sciences 1 , Beijing 100190,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-2772-8687","authenticated-orcid":false,"given":"Tien-Dat","family":"Tran","sequence":"additional","affiliation":[{"name":"Department of Physics, University of Hong Kong 5 , Hong Kong SAR 999077,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3772-3379","authenticated-orcid":false,"given":"Tran Trung","family":"Luu","sequence":"additional","affiliation":[{"name":"Department of Physics, University of Hong Kong 5 , Hong Kong SAR 999077,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7746-2113","authenticated-orcid":false,"given":"Pengju","family":"Zhang","sequence":"additional","affiliation":[{"name":"Institute of Physics, Chinese Academy of Sciences 1 , Beijing 100190,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"317","published-online":{"date-parts":[[2026,1,28]]},"reference":[{"key":"2026012808385529000_c1","doi-asserted-by":"publisher","first-page":"1689","DOI":"10.1126\/science.1059413","article-title":"Observation of a train of attosecond pulses from high harmonic generation","volume":"292","year":"2001","journal-title":"Science"},{"key":"2026012808385529000_c2","doi-asserted-by":"publisher","first-page":"509","DOI":"10.1038\/35107000","article-title":"Attosecond metrology","volume":"414","year":"2001","journal-title":"Nature"},{"key":"2026012808385529000_c3","doi-asserted-by":"publisher","first-page":"893","DOI":"10.1126\/science.aao7043","article-title":"Photoionization in the time and frequency domain","volume":"358","year":"2017","journal-title":"Science"},{"key":"2026012808385529000_c4","doi-asserted-by":"publisher","first-page":"073001","DOI":"10.1103\/physrevlett.122.073001","article-title":"Terahertz-field-induced time shifts in atomic photoemission","volume":"122","year":"2019","journal-title":"Phys. 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