Pub Date : 2023-06-26DOI: 10.1109/CLEO/Europe-EQEC57999.2023.10232551
Michael Zwilich, Florian Schepers, C. Fallnich
Optical resonators are routinely used as optical spectrum analyzers or mode-cleaners [1], [2]. However, as shown in this work, their spectral and spatial filtering properties can also be utilized to convert longitudinal to transverse mode-locked states and vice versa. For longitudinal to transverse conversion the spectral components of an incident longitudinal mode-locked beam are matched to transverse mode resonances of an empty optical cavity. As a result, all spectral components are transmitted simultaneously and converted into transverse modes. Thus, an amplitude-modulated, i.e. longitudinal mode-locked, beam is converted into a transverse mode-locked beam that rapidly oscillates across the transverse plane. This conversion scheme allows to control the set of locked transverse modes and their respective amplitudes separately, which improves the generation of transverse mode-locked states compared to their excitation in laser-active cavities [3]–[5].
{"title":"Conversion of Mode-Locked States within an Empty Optical Resonator","authors":"Michael Zwilich, Florian Schepers, C. Fallnich","doi":"10.1109/CLEO/Europe-EQEC57999.2023.10232551","DOIUrl":"https://doi.org/10.1109/CLEO/Europe-EQEC57999.2023.10232551","url":null,"abstract":"Optical resonators are routinely used as optical spectrum analyzers or mode-cleaners [1], [2]. However, as shown in this work, their spectral and spatial filtering properties can also be utilized to convert longitudinal to transverse mode-locked states and vice versa. For longitudinal to transverse conversion the spectral components of an incident longitudinal mode-locked beam are matched to transverse mode resonances of an empty optical cavity. As a result, all spectral components are transmitted simultaneously and converted into transverse modes. Thus, an amplitude-modulated, i.e. longitudinal mode-locked, beam is converted into a transverse mode-locked beam that rapidly oscillates across the transverse plane. This conversion scheme allows to control the set of locked transverse modes and their respective amplitudes separately, which improves the generation of transverse mode-locked states compared to their excitation in laser-active cavities [3]–[5].","PeriodicalId":19477,"journal":{"name":"Oceans","volume":"23 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81116559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-26DOI: 10.1109/CLEO/Europe-EQEC57999.2023.10231405
Yongjin Na, Jungwon Kim
We demonstrate ultrafast time-of-flight detection with sub-nm-precision and ~6-mm non-ambiguity-range by electro-optic sampling of optical frequency combs. When combined with space-to-wavelength encoding, massively parallel time-of-flight detection of >1000 pulses can be realized with 260-megapixels/s pixel-rate.
{"title":"Ultrafast and Subnanometer-Precision Time-of-Flight Detection of >1000 Space-to-Wavelength-Encoded Optical Pulses","authors":"Yongjin Na, Jungwon Kim","doi":"10.1109/CLEO/Europe-EQEC57999.2023.10231405","DOIUrl":"https://doi.org/10.1109/CLEO/Europe-EQEC57999.2023.10231405","url":null,"abstract":"We demonstrate ultrafast time-of-flight detection with sub-nm-precision and ~6-mm non-ambiguity-range by electro-optic sampling of optical frequency combs. When combined with space-to-wavelength encoding, massively parallel time-of-flight detection of >1000 pulses can be realized with 260-megapixels/s pixel-rate.","PeriodicalId":19477,"journal":{"name":"Oceans","volume":"67 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81119766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-26DOI: 10.1109/CLEO/Europe-EQEC57999.2023.10232140
Valeria V. Belloni, Mostafa Hassan, L. Furfaro, L. Froehly, C. Billet, R. Giust, F. Courvoisier
The interaction between laser and matter can efficiently produce very interesting structures. Despite the flexibility of the conventional Gaussian beam, other beam shapes bring advantages in matter structuring. Applying a conical phase, the Gaussian beam can be shaped in a zeroth order Bessel beam with its characteristic high aspect ratio central core. The Bessel beam gives interesting results in single shot drilling and fast-cutting of thick material [1], [2]. Moreover, by applying an additional vortex phase, a higher order Bessel beam is obtained with a hollow cylindrical central core. A single shot of this beam can create an elongated zone of higher density due to matter compression [3]. On the other side, a vortex phase on a gaussian beam gives a doughnut shaped beam carrying optical angular momentum that is capable of generating spiraling nano-needles [4].
{"title":"High Aspect Ratio Nano-Pillars Fabricated by a Single Pulse of Ultrafast Bessel Beam","authors":"Valeria V. Belloni, Mostafa Hassan, L. Furfaro, L. Froehly, C. Billet, R. Giust, F. Courvoisier","doi":"10.1109/CLEO/Europe-EQEC57999.2023.10232140","DOIUrl":"https://doi.org/10.1109/CLEO/Europe-EQEC57999.2023.10232140","url":null,"abstract":"The interaction between laser and matter can efficiently produce very interesting structures. Despite the flexibility of the conventional Gaussian beam, other beam shapes bring advantages in matter structuring. Applying a conical phase, the Gaussian beam can be shaped in a zeroth order Bessel beam with its characteristic high aspect ratio central core. The Bessel beam gives interesting results in single shot drilling and fast-cutting of thick material [1], [2]. Moreover, by applying an additional vortex phase, a higher order Bessel beam is obtained with a hollow cylindrical central core. A single shot of this beam can create an elongated zone of higher density due to matter compression [3]. On the other side, a vortex phase on a gaussian beam gives a doughnut shaped beam carrying optical angular momentum that is capable of generating spiraling nano-needles [4].","PeriodicalId":19477,"journal":{"name":"Oceans","volume":"23 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85408137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-26DOI: 10.1109/CLEO/Europe-EQEC57999.2023.10232739
Théo Martel, R. Braive
Purely optical photonic crystals have been intensively studied with SNOM (Scanning Near-field Optical Microscopy) techniques [1], [2] giving important information about losses channels and confinement of photons at the nanoscale. Recently, photonic crystals have been considered for their optomechanical properties, which would be of great interest e.g. for new GHz integrated oscillators [3] or quantum applications [4]. In these crystals, experimental observations match results from numerical simulations of mechanical modes. However, the spatial distribution of phonons is deduced from the simulations without any experimental demonstration, yet. The in situ investigation of the mechanical losses and mode extension would provide interesting hints on the design optimization of optomechanical crystals, which would allow to improve the performance of these new devices.
{"title":"Direct Determination of Optomechanical Photonic Crystal Mechanical Mode Profile via Quasi Near-Field Perturbation","authors":"Théo Martel, R. Braive","doi":"10.1109/CLEO/Europe-EQEC57999.2023.10232739","DOIUrl":"https://doi.org/10.1109/CLEO/Europe-EQEC57999.2023.10232739","url":null,"abstract":"Purely optical photonic crystals have been intensively studied with SNOM (Scanning Near-field Optical Microscopy) techniques [1], [2] giving important information about losses channels and confinement of photons at the nanoscale. Recently, photonic crystals have been considered for their optomechanical properties, which would be of great interest e.g. for new GHz integrated oscillators [3] or quantum applications [4]. In these crystals, experimental observations match results from numerical simulations of mechanical modes. However, the spatial distribution of phonons is deduced from the simulations without any experimental demonstration, yet. The in situ investigation of the mechanical losses and mode extension would provide interesting hints on the design optimization of optomechanical crystals, which would allow to improve the performance of these new devices.","PeriodicalId":19477,"journal":{"name":"Oceans","volume":"73 1","pages":"01-01"},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85820293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-26DOI: 10.1109/cleo/europe-eqec57999.2023.10231620
Åsa Haglund, F. Hjort, J. Enslin, M. Bergmann, M. Cobet, G. Cardinali, N. Prokop, Lars Persson, Estrella Torres, Sarina Graupeter, Massimo Grigoletto, M. Guttmann, L. Sulmoni, N. Lobo-Ploch, T. Kolbe, J. Ciers, T. Wernicke, M. Kneissl
We daily rely upon vertical-cavity surface-emitting lasers (VCSELs) for facial recognition and data communication. These lasers are now experiencing exponential growth and serves in other applications as well such as oxygen monitoring in combustion processes and in anesthetized patients in hospitals and as a source of heating in industry in the form of a large-sized array. The large interest for this laser class is linked to its beneficial qualities such as low threshold current, circular-symmetric low-divergent output beam, high efficiency, compactness, and low fabrication cost due to on-wafer testing. Due to these advantages, there is a strong push to realize VCSELs in other wavelength regimes, beyond the commercially available infrared and red. This would open completely new markets such as flood lights, projectors, sterilization, and medical diagnosis and treatment.
{"title":"The Quest for Ultraviolet Vertical-Cavity Surface-Emitting Lasers","authors":"Åsa Haglund, F. Hjort, J. Enslin, M. Bergmann, M. Cobet, G. Cardinali, N. Prokop, Lars Persson, Estrella Torres, Sarina Graupeter, Massimo Grigoletto, M. Guttmann, L. Sulmoni, N. Lobo-Ploch, T. Kolbe, J. Ciers, T. Wernicke, M. Kneissl","doi":"10.1109/cleo/europe-eqec57999.2023.10231620","DOIUrl":"https://doi.org/10.1109/cleo/europe-eqec57999.2023.10231620","url":null,"abstract":"We daily rely upon vertical-cavity surface-emitting lasers (VCSELs) for facial recognition and data communication. These lasers are now experiencing exponential growth and serves in other applications as well such as oxygen monitoring in combustion processes and in anesthetized patients in hospitals and as a source of heating in industry in the form of a large-sized array. The large interest for this laser class is linked to its beneficial qualities such as low threshold current, circular-symmetric low-divergent output beam, high efficiency, compactness, and low fabrication cost due to on-wafer testing. Due to these advantages, there is a strong push to realize VCSELs in other wavelength regimes, beyond the commercially available infrared and red. This would open completely new markets such as flood lights, projectors, sterilization, and medical diagnosis and treatment.","PeriodicalId":19477,"journal":{"name":"Oceans","volume":"66 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86057416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-26DOI: 10.1109/cleo/europe-eqec57999.2023.10232754
B. Lochocki, Aleksandra Ivanina, Akje Bandhoe, Johannes F. de Boer, Lyubov V. Amitonova
Fig. 1: Compressive Imaging (CI) results for two different binary samples. The reconstruction of $128 times 128$ pixels is computed from 1000 speckle patterns over a sweeping bandwidth of 27.5 nm
{"title":"Wavelength Scanning Multimode Fiber Imaging","authors":"B. Lochocki, Aleksandra Ivanina, Akje Bandhoe, Johannes F. de Boer, Lyubov V. Amitonova","doi":"10.1109/cleo/europe-eqec57999.2023.10232754","DOIUrl":"https://doi.org/10.1109/cleo/europe-eqec57999.2023.10232754","url":null,"abstract":"Fig. 1: Compressive Imaging (CI) results for two different binary samples. The reconstruction of $128 times 128$ pixels is computed from 1000 speckle patterns over a sweeping bandwidth of 27.5 nm","PeriodicalId":19477,"journal":{"name":"Oceans","volume":"86 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84021373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-26DOI: 10.1109/CLEO/Europe-EQEC57999.2023.10232283
David Castolló-Lurbe, C. Cuadrado-Laborde, Enrique Silvestre, A. Díez, M. V. Andrés
Contrary to traditional views considering loss a limiting factor for nonlinear photonics applications, a judicious loss management is currently playing a crucial role in different research areas in nonlinear optics ranging from plasmonics and $mathcal{PT}$-symmetric systems to pulse propagation in waveguides with 2D materials [1] or dispersive nonlinearities [2]. As this physics relies on interplays between nonlinear, dispersive (or diffractive) and loss (or gain) effects, an accurate measurement of the nonlinear coefficient $gamma$ cannot disregard either chromatic dispersion $beta_{2}$ or linear loss $alpha$, whereas state-of-the-art techniques require dispersionless [3] or lossless waveguides [4]. Moreover, such a measurement would aid theoretical ongoing research in discriminating competing nonlinear models founded on different assumptions [5]. Here we demonstrate a procedure for measuring $beta_{2}/gamma$, and hence $gamma$ if $beta_{2}$ is available, under conditions where dispersion and loss are comparable to nonlinear effects.
{"title":"Measuring Nonlinearities Under High Dispersion and Loss","authors":"David Castolló-Lurbe, C. Cuadrado-Laborde, Enrique Silvestre, A. Díez, M. V. Andrés","doi":"10.1109/CLEO/Europe-EQEC57999.2023.10232283","DOIUrl":"https://doi.org/10.1109/CLEO/Europe-EQEC57999.2023.10232283","url":null,"abstract":"Contrary to traditional views considering loss a limiting factor for nonlinear photonics applications, a judicious loss management is currently playing a crucial role in different research areas in nonlinear optics ranging from plasmonics and $mathcal{PT}$-symmetric systems to pulse propagation in waveguides with 2D materials [1] or dispersive nonlinearities [2]. As this physics relies on interplays between nonlinear, dispersive (or diffractive) and loss (or gain) effects, an accurate measurement of the nonlinear coefficient $gamma$ cannot disregard either chromatic dispersion $beta_{2}$ or linear loss $alpha$, whereas state-of-the-art techniques require dispersionless [3] or lossless waveguides [4]. Moreover, such a measurement would aid theoretical ongoing research in discriminating competing nonlinear models founded on different assumptions [5]. Here we demonstrate a procedure for measuring $beta_{2}/gamma$, and hence $gamma$ if $beta_{2}$ is available, under conditions where dispersion and loss are comparable to nonlinear effects.","PeriodicalId":19477,"journal":{"name":"Oceans","volume":"92 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84041126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-26DOI: 10.1109/CLEO/Europe-EQEC57999.2023.10232486
N. M. Palakkool, M. Taverne, D. Rezaie, H. Awachi, Y.-S. J. Chen, J. G. Rarity, C.-C. Huang, Y. D. Ho
The areal energy density of fuel cells and batteries is proportional to the mass loading of the electrochemically active materials. As can be expected, the development of 3D electrodes holds promise for the implementation of highly efficient energy and power capabilities of fuel cells [1] and batteries [2]. Despite the development of some proof-of-concept examples, currently there are no 3D electrodes that simultaneously possess dimensional compatibility, high mass activity, and high electrochemical performance. This problem is hindering successful implementation of energy applications. Hence, successful development of 3D electrodes with all these features is essential for further advancement of energy applications.
{"title":"Determination of the Inner Surface Area of 3D Wavelength Scale Structures by Using Angle-resolved Fourier Image Spectroscopy","authors":"N. M. Palakkool, M. Taverne, D. Rezaie, H. Awachi, Y.-S. J. Chen, J. G. Rarity, C.-C. Huang, Y. D. Ho","doi":"10.1109/CLEO/Europe-EQEC57999.2023.10232486","DOIUrl":"https://doi.org/10.1109/CLEO/Europe-EQEC57999.2023.10232486","url":null,"abstract":"The areal energy density of fuel cells and batteries is proportional to the mass loading of the electrochemically active materials. As can be expected, the development of 3D electrodes holds promise for the implementation of highly efficient energy and power capabilities of fuel cells [1] and batteries [2]. Despite the development of some proof-of-concept examples, currently there are no 3D electrodes that simultaneously possess dimensional compatibility, high mass activity, and high electrochemical performance. This problem is hindering successful implementation of energy applications. Hence, successful development of 3D electrodes with all these features is essential for further advancement of energy applications.","PeriodicalId":19477,"journal":{"name":"Oceans","volume":"15 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84197001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-26DOI: 10.1109/CLEO/Europe-EQEC57999.2023.10231551
Florin Lucian Constantin
The nature of dark matter is unknown despite the work performed in high energy physics toward its direct detection [1]. Couplings between ultralight dark matter candidates to the particles of the Standard Model can induce temporal variations of the fundamental constants that were probed through precision measurements with atoms and molecules [2]. Transitions between near-resonant energy levels of atoms or molecules were addressed in dark matter searches [3] to benefit from their enhanced sensitivity to the variations of the fundamental constants. Acetylene transitions were exploited as frequency references in the $1.5 mumathrm{m}$ domain. This work addresses the potential for dark matter searches from transitions between near-resonant energy levels of 12C2H2.
{"title":"Enhanced Sensitivity to Bosonic Ultralight Dark Matter from Acetylene Transitions between Near-Degenerate Vibrational Modes","authors":"Florin Lucian Constantin","doi":"10.1109/CLEO/Europe-EQEC57999.2023.10231551","DOIUrl":"https://doi.org/10.1109/CLEO/Europe-EQEC57999.2023.10231551","url":null,"abstract":"The nature of dark matter is unknown despite the work performed in high energy physics toward its direct detection [1]. Couplings between ultralight dark matter candidates to the particles of the Standard Model can induce temporal variations of the fundamental constants that were probed through precision measurements with atoms and molecules [2]. Transitions between near-resonant energy levels of atoms or molecules were addressed in dark matter searches [3] to benefit from their enhanced sensitivity to the variations of the fundamental constants. Acetylene transitions were exploited as frequency references in the $1.5 mumathrm{m}$ domain. This work addresses the potential for dark matter searches from transitions between near-resonant energy levels of 12C2H2.","PeriodicalId":19477,"journal":{"name":"Oceans","volume":"14 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78338634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-26DOI: 10.1109/CLEO/Europe-EQEC57999.2023.10232533
M. Tani, Kakeru Sasaki, Yasushi Shinohara, Kenichi L. Ishikawa
Over the past decades, the interaction between femtosecond intense lasers and semiconductors or dielectrics has been attracting significant attention as for high harmonic generation [1], high-quality laser micromachining without the thermal damage [2]. Several experimental and theoretical studies have reported that the use of two-color laser pulses enables highly efficient laser ablation of transparent materials compared to a single-color pump pulse [3], [4]. In the present work, to elucidate how two-color femtosecond laser pulses deposit energy to electrons in semiconductors and dielectrics, we utilize the time-dependent density functional theory (TDDFT) and examine the energy absorption of crystalline silicon under overlapped two-color [ultraviolet (UV) and infrared (IR)] intense femtosecond laser pulses as a function of relative intensity with the total fluence conserved. The deposited energy is dramatically enhanced by two-color laser field and maximized when they are equally mixed [see Fig. 1(a)]. The interplay between intraband electron motion in the valence band (before excitation) driven by the IR component and resonant valence-to-conduction interband excitation (carrier injection) induced by the UV component is identified as the underlying mechanism. Interestingly, the former plays an influential role, increases the excited electrons [see Fig. 1(b)]. The effect of multiple multiphoton absorption paths, relative phase of carrier waves, or intraband motion of the created carriers in the conduction band play a minor role.
{"title":"Enhanced Energy Absorption and Electron Excitation in Crystalline Silicon Induced by Two-Color Intense Femtosecond Laser Pulses","authors":"M. Tani, Kakeru Sasaki, Yasushi Shinohara, Kenichi L. Ishikawa","doi":"10.1109/CLEO/Europe-EQEC57999.2023.10232533","DOIUrl":"https://doi.org/10.1109/CLEO/Europe-EQEC57999.2023.10232533","url":null,"abstract":"Over the past decades, the interaction between femtosecond intense lasers and semiconductors or dielectrics has been attracting significant attention as for high harmonic generation [1], high-quality laser micromachining without the thermal damage [2]. Several experimental and theoretical studies have reported that the use of two-color laser pulses enables highly efficient laser ablation of transparent materials compared to a single-color pump pulse [3], [4]. In the present work, to elucidate how two-color femtosecond laser pulses deposit energy to electrons in semiconductors and dielectrics, we utilize the time-dependent density functional theory (TDDFT) and examine the energy absorption of crystalline silicon under overlapped two-color [ultraviolet (UV) and infrared (IR)] intense femtosecond laser pulses as a function of relative intensity with the total fluence conserved. The deposited energy is dramatically enhanced by two-color laser field and maximized when they are equally mixed [see Fig. 1(a)]. The interplay between intraband electron motion in the valence band (before excitation) driven by the IR component and resonant valence-to-conduction interband excitation (carrier injection) induced by the UV component is identified as the underlying mechanism. Interestingly, the former plays an influential role, increases the excited electrons [see Fig. 1(b)]. The effect of multiple multiphoton absorption paths, relative phase of carrier waves, or intraband motion of the created carriers in the conduction band play a minor role.","PeriodicalId":19477,"journal":{"name":"Oceans","volume":"25 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78363634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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