Coherent Control of Single Molecules via Phase-Shaped Two-Photon Excitation at Room Temperature
Coherent control has been achieved in atoms and small molecules in gas phase during the past few decades. An intriguing demonstration of coherent control is a so-called “dark pulse” that cancels 2-photon transition probabilities despite exposing the target to the full power spectrum of transform-lim...
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American Association for the Advancement of Science (AAAS)
2025-01-01
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| Series: | Ultrafast Science |
| Online Access: | https://spj.science.org/doi/10.34133/ultrafastscience.0086 |
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| author | Xin-peng Xu Tobias M. Herkenrath Ullrich Scherf Richard Hildner |
| author_facet | Xin-peng Xu Tobias M. Herkenrath Ullrich Scherf Richard Hildner |
| author_sort | Xin-peng Xu |
| collection | DOAJ |
| description | Coherent control has been achieved in atoms and small molecules in gas phase during the past few decades. An intriguing demonstration of coherent control is a so-called “dark pulse” that cancels 2-photon transition probabilities despite exposing the target to the full power spectrum of transform-limited laser pulses. However, for larger functional molecules in condensed phase at room temperature, ensemble measurements do typically not allow exerting full control over competing pathways due to the unavoidable influence of the surrounding (mostly complex) environment. Here, we demonstrate room-temperature coherent control exploiting a nonresonant 2-photon transition into a higher excited state of single conjugated polymer chains embedded in a disordered matrix, including proof-of-principle experiments on bulk films. To manipulate the 2-photon transition probability, we exploit complex pulse sequences, created by a systematically varied cosinusoidal spectral phase applied to the excitation laser spectrum. For single molecules, the phase-dependent response varies from molecule to molecule, which reflects the spectral heterogeneity (position, linewidth) of their 2-photon transitions. These data indicate that coherent control of single molecules requires optimization of parameters for each individual molecule. The experimental data are reproduced by a simple model that allows to directly retrieve the 2-photon absorption spectrum of each single molecule. Our coherent-control approach is a powerful and robust way to obtain spectral characteristics of higher excited states of single molecules and to manipulate the excited-state dynamics in condensed phase at room temperature. It holds the potential to be useful for the characterization of complex organic functional materials. |
| format | Article |
| id | doaj-art-515ffe45938342738c2c91652be1d33d |
| institution | Kabale University |
| issn | 2765-8791 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | American Association for the Advancement of Science (AAAS) |
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| spelling | doaj-art-515ffe45938342738c2c91652be1d33d2025-02-07T08:00:37ZengAmerican Association for the Advancement of Science (AAAS)Ultrafast Science2765-87912025-01-01510.34133/ultrafastscience.0086Coherent Control of Single Molecules via Phase-Shaped Two-Photon Excitation at Room TemperatureXin-peng Xu0Tobias M. Herkenrath1Ullrich Scherf2Richard Hildner3Zernike Institute for Advanced Materials, University of Groningen, 9747AG Groningen, Netherlands.Fachbereich C - Mathematik und Naturwissenschaften and Wuppertal Center for Smart Materials and Systems (CM@S), Bergische Universität Wuppertal, D-42119 Wuppertal, Germany.Fachbereich C - Mathematik und Naturwissenschaften and Wuppertal Center for Smart Materials and Systems (CM@S), Bergische Universität Wuppertal, D-42119 Wuppertal, Germany.Zernike Institute for Advanced Materials, University of Groningen, 9747AG Groningen, Netherlands.Coherent control has been achieved in atoms and small molecules in gas phase during the past few decades. An intriguing demonstration of coherent control is a so-called “dark pulse” that cancels 2-photon transition probabilities despite exposing the target to the full power spectrum of transform-limited laser pulses. However, for larger functional molecules in condensed phase at room temperature, ensemble measurements do typically not allow exerting full control over competing pathways due to the unavoidable influence of the surrounding (mostly complex) environment. Here, we demonstrate room-temperature coherent control exploiting a nonresonant 2-photon transition into a higher excited state of single conjugated polymer chains embedded in a disordered matrix, including proof-of-principle experiments on bulk films. To manipulate the 2-photon transition probability, we exploit complex pulse sequences, created by a systematically varied cosinusoidal spectral phase applied to the excitation laser spectrum. For single molecules, the phase-dependent response varies from molecule to molecule, which reflects the spectral heterogeneity (position, linewidth) of their 2-photon transitions. These data indicate that coherent control of single molecules requires optimization of parameters for each individual molecule. The experimental data are reproduced by a simple model that allows to directly retrieve the 2-photon absorption spectrum of each single molecule. Our coherent-control approach is a powerful and robust way to obtain spectral characteristics of higher excited states of single molecules and to manipulate the excited-state dynamics in condensed phase at room temperature. It holds the potential to be useful for the characterization of complex organic functional materials.https://spj.science.org/doi/10.34133/ultrafastscience.0086 |
| spellingShingle | Xin-peng Xu Tobias M. Herkenrath Ullrich Scherf Richard Hildner Coherent Control of Single Molecules via Phase-Shaped Two-Photon Excitation at Room Temperature Ultrafast Science |
| title | Coherent Control of Single Molecules via Phase-Shaped Two-Photon Excitation at Room Temperature |
| title_full | Coherent Control of Single Molecules via Phase-Shaped Two-Photon Excitation at Room Temperature |
| title_fullStr | Coherent Control of Single Molecules via Phase-Shaped Two-Photon Excitation at Room Temperature |
| title_full_unstemmed | Coherent Control of Single Molecules via Phase-Shaped Two-Photon Excitation at Room Temperature |
| title_short | Coherent Control of Single Molecules via Phase-Shaped Two-Photon Excitation at Room Temperature |
| title_sort | coherent control of single molecules via phase shaped two photon excitation at room temperature |
| url | https://spj.science.org/doi/10.34133/ultrafastscience.0086 |
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