title: Resonant absorption induced fast melting studied with mid-IR QCLs.
abstract: We demonstrate the use of a pump-probe setup based on two mid-infrared quantum cascade lasers (QCLs) to investigate the melting and crystallization of materials through resonant absorption. A combination of pump and probe beams fulfills the two-color synchronous detection. Furthermore, narrow linewidth advances the accuracy of measurements and the character of broad tuning range of QCLs enables wide applications in various sample and multiple structures. 1-Eicosene was selected as a simple model system to verify the feasibility of this method. A pulsed QCL was tuned to the absorption peak of CH2bending vibration at 1467 cm-1to resonantly heat the sample. The other QCL in continuous mode was tuned to 1643 cm-1corresponding the C=C stretching vibration to follow the fast melting dynamics. By monitoring the transmission intensity variation of pump and probe beams during pump-probe experiments, the resonant absorption induced fast melting and re-crystallization of 1-Eicosene can be studied. Results show that the thermal effect and melting behaviors strongly depend on the pump wavelength (resonant or non-resonant) and energy, as well as the pump time. The realization and detection of melting and recrystallization can be performed in tens of milliseconds, which improves the time resolution of melting process study based on general mid-infrared spectrum by orders of magnitude. The availability of resonant heating and detections based on mid-infrared QCLs is expected to enable new applications in melting study.
authors.affiliation: National Synchrotron Radiation Laboratory, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Lu
authors.affiliation: National Synchrotron Radiation Laboratory, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Yankun
authors.initials: Y
authors.lastname: Lv
authors.affiliation: National Synchrotron Radiation Laboratory, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Youxin
authors.initials: Y
authors.lastname: Ji
authors.affiliation: National Synchrotron Radiation Laboratory, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Tang
authors.affiliation: National Synchrotron Radiation Laboratory, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Zeming
authors.initials: Z
authors.lastname: Qi
authors.affiliation: National Synchrotron Radiation Laboratory, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Liangbin
authors.identifier: 0000000165507070
authors.initials: L
authors.lastname: Li