Laser–Metal Interaction with a Pulse Shorter than the Ion Period: Ablation Threshold, Electron Emission and Ion Explosion
The laser energy per unit surface, necessary to trigger material removal, decreases with the pulse shortening, becoming pulse–time independent in the sub-picosecond range. These pulses are shorter than the electron-to-ion energy transfer time and electronic heat conduction time, minimising the energ...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-06-01
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| Series: | Nanomaterials |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2079-4991/13/11/1796 |
| _version_ | 1797597010007687168 |
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| author | Eugene G. Gamaly Saulius Juodkazis |
| author_facet | Eugene G. Gamaly Saulius Juodkazis |
| author_sort | Eugene G. Gamaly |
| collection | DOAJ |
| description | The laser energy per unit surface, necessary to trigger material removal, decreases with the pulse shortening, becoming pulse–time independent in the sub-picosecond range. These pulses are shorter than the electron-to-ion energy transfer time and electronic heat conduction time, minimising the energy losses. Electrons receiving an energy larger than the threshold drag the ions off the surface in the mode of electrostatic ablation. We show that a pulse shorter than the ion period (Shorter-the-Limit (StL)) ejects conduction electrons with an energy larger than the work function (from a metal), leaving the bare ions immobile in a few atomic layers. Electron emission is followed by the bare ion’s explosion, ablation, and THz radiation from the expanding plasma. We compare this phenomenon to the classic photo effect and nanocluster Coulomb explosions, and show differences and consider possibilities for detecting new modes of ablation experimentally via emitted THz radiation. We also consider the applications of high-precision nano-machining with this low intensity irradiation. |
| first_indexed | 2024-03-11T03:00:46Z |
| format | Article |
| id | doaj.art-7edd49ba91c54d59aa6042aa7589bd9c |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-11T03:00:46Z |
| publishDate | 2023-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-7edd49ba91c54d59aa6042aa7589bd9c2023-11-18T08:19:38ZengMDPI AGNanomaterials2079-49912023-06-011311179610.3390/nano13111796Laser–Metal Interaction with a Pulse Shorter than the Ion Period: Ablation Threshold, Electron Emission and Ion ExplosionEugene G. Gamaly0Saulius Juodkazis1Laser Physics Centre, Department of Quantum Science and Technology, Research School of Physics, The Australian National University, Canberra, ACT 2601, AustraliaOptical Sciences Centre (OSC) and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Swinburne University of Technology, Hawthorn, VIC 3122, AustraliaThe laser energy per unit surface, necessary to trigger material removal, decreases with the pulse shortening, becoming pulse–time independent in the sub-picosecond range. These pulses are shorter than the electron-to-ion energy transfer time and electronic heat conduction time, minimising the energy losses. Electrons receiving an energy larger than the threshold drag the ions off the surface in the mode of electrostatic ablation. We show that a pulse shorter than the ion period (Shorter-the-Limit (StL)) ejects conduction electrons with an energy larger than the work function (from a metal), leaving the bare ions immobile in a few atomic layers. Electron emission is followed by the bare ion’s explosion, ablation, and THz radiation from the expanding plasma. We compare this phenomenon to the classic photo effect and nanocluster Coulomb explosions, and show differences and consider possibilities for detecting new modes of ablation experimentally via emitted THz radiation. We also consider the applications of high-precision nano-machining with this low intensity irradiation.https://www.mdpi.com/2079-4991/13/11/1796ultra-short laser pulseslaser pulses shorter than the ion periodnon-equilibrium ablationCoulomb explosionmicromachiningTHz emission |
| spellingShingle | Eugene G. Gamaly Saulius Juodkazis Laser–Metal Interaction with a Pulse Shorter than the Ion Period: Ablation Threshold, Electron Emission and Ion Explosion Nanomaterials ultra-short laser pulses laser pulses shorter than the ion period non-equilibrium ablation Coulomb explosion micromachining THz emission |
| title | Laser–Metal Interaction with a Pulse Shorter than the Ion Period: Ablation Threshold, Electron Emission and Ion Explosion |
| title_full | Laser–Metal Interaction with a Pulse Shorter than the Ion Period: Ablation Threshold, Electron Emission and Ion Explosion |
| title_fullStr | Laser–Metal Interaction with a Pulse Shorter than the Ion Period: Ablation Threshold, Electron Emission and Ion Explosion |
| title_full_unstemmed | Laser–Metal Interaction with a Pulse Shorter than the Ion Period: Ablation Threshold, Electron Emission and Ion Explosion |
| title_short | Laser–Metal Interaction with a Pulse Shorter than the Ion Period: Ablation Threshold, Electron Emission and Ion Explosion |
| title_sort | laser metal interaction with a pulse shorter than the ion period ablation threshold electron emission and ion explosion |
| topic | ultra-short laser pulses laser pulses shorter than the ion period non-equilibrium ablation Coulomb explosion micromachining THz emission |
| url | https://www.mdpi.com/2079-4991/13/11/1796 |
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