Pub Date : 2025-03-12DOI: 10.1021/acsphotonics.4c02388
Alireza Khoshzaban, Alessandro Magazzú, Maria Grazia Donato, Onofrio M. Maragò, Mehmet Burcin Unlu, M. Natali Cizmeciyan, Parviz Elahi
Janus particles, with their flexible chemistry and multifunctionality, have broadened the scope of the optical manipulation field as an emerging class of materials. Laser-based manipulation is particularly promising for half-metal-coated particles, offering a platform to study optical and thermal effects. However, the role of the laser’s operation regime in particle behavior needs to be understood better. Hence, in this work, we studied the interaction of nanosecond-pulsed lasers on 4.1 μm Au-Janus particles with a 100 nm gold cap. We focused on the interaction in three sections: (1) We observed three pulse energy influence regimes: In the low-influence regime (less than ∼10 nJ), the particle maintains its intrinsic Brownian motion. In the medium-influence regime (less than ∼40 nJ), the particle exhibits an extended range of motion. In the high-influence regime (higher than ∼40 nJ), the particle undergoes superdiffusion and establishes a new equilibrium position. (2) During optical manipulation trials, a threshold pulse energy of 4 nJ (average power of 40 μW) was sufficient to move Au-Janus particles against the laser spot. We achieved translation velocities of 0.9–5.1 μm/s at 4–50 nJ. (3) The gold cap is damaged at 20 nJ (fluence of 0.7 J/cm2) when the laser is focused on the particle, consistent with theoretical predictions, and the ablation process generates micro- and submicrometer gold particles. These findings reveal the potential of pulsed lasers for precise, power-efficient manipulation of Janus particles, advancing our understanding of laser–particle interactions and opening new pathways for optical manipulation applications.
{"title":"Dynamics of Pulsed-Laser Interaction with Janus Particles","authors":"Alireza Khoshzaban, Alessandro Magazzú, Maria Grazia Donato, Onofrio M. Maragò, Mehmet Burcin Unlu, M. Natali Cizmeciyan, Parviz Elahi","doi":"10.1021/acsphotonics.4c02388","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02388","url":null,"abstract":"Janus particles, with their flexible chemistry and multifunctionality, have broadened the scope of the optical manipulation field as an emerging class of materials. Laser-based manipulation is particularly promising for half-metal-coated particles, offering a platform to study optical and thermal effects. However, the role of the laser’s operation regime in particle behavior needs to be understood better. Hence, in this work, we studied the interaction of nanosecond-pulsed lasers on 4.1 μm Au-Janus particles with a 100 nm gold cap. We focused on the interaction in three sections: (1) We observed three pulse energy influence regimes: In the low-influence regime (less than ∼10 nJ), the particle maintains its intrinsic Brownian motion. In the medium-influence regime (less than ∼40 nJ), the particle exhibits an extended range of motion. In the high-influence regime (higher than ∼40 nJ), the particle undergoes superdiffusion and establishes a new equilibrium position. (2) During optical manipulation trials, a threshold pulse energy of 4 nJ (average power of 40 μW) was sufficient to move Au-Janus particles against the laser spot. We achieved translation velocities of 0.9–5.1 μm/s at 4–50 nJ. (3) The gold cap is damaged at 20 nJ (fluence of 0.7 J/cm<sup>2</sup>) when the laser is focused on the particle, consistent with theoretical predictions, and the ablation process generates micro- and submicrometer gold particles. These findings reveal the potential of pulsed lasers for precise, power-efficient manipulation of Janus particles, advancing our understanding of laser–particle interactions and opening new pathways for optical manipulation applications.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"17 1 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-12DOI: 10.1021/acsphotonics.4c02545
Rafael Quintero-Bermudez, Lauren Drescher, Vincent Eggers, Kevin Gulu Xiong, Stephen R. Leone
Transient grating spectroscopy has become a mainstay among metal and semiconductor characterization techniques. Here, we extend the technique toward the shortest achievable time scales by using tabletop high-harmonic generation of attosecond extreme ultraviolet (XUV) pulses that diffract from transient gratings generated with sub-5 fs near-infrared (NIR) pulses. We demonstrate the power of attosecond transient grating spectroscopy (ATGS) by investigating the ultrafast photoexcited dynamics in an Sb semimetal thin film. ATGS provides an element-specific, background-free signal unfettered by spectral congestion, in contrast to transient absorption spectroscopy. With ATGS measurements in Sb polycrystalline thin films, we observe the generation of coherent phonons and investigate the lattice and carrier dynamics. Among the latter processes, we extract carrier thermalization, hot carrier cooling, and electron–hole recombination, which are on the order of 20 fs, 50 fs, and 2 ps time scales, respectively. Furthermore, the simultaneous collection of transient absorption and transient grating data allows us to extract the total complex dielectric constant in the sample dynamics with a single measurement, including the real-valued refractive index, from which we are also able to investigate carrier–phonon interactions and longer-lived phonon dynamics. The outlined experimental technique expands the capabilities of transient grating spectroscopy and attosecond spectroscopies by providing a wealth of information concerning carrier and lattice dynamics with an element-selective technique at the shortest achievable time scales.
{"title":"Attosecond Transient Grating Spectroscopy with Near-Infrared Grating Pulses and an Extreme Ultraviolet Diffracted Probe","authors":"Rafael Quintero-Bermudez, Lauren Drescher, Vincent Eggers, Kevin Gulu Xiong, Stephen R. Leone","doi":"10.1021/acsphotonics.4c02545","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02545","url":null,"abstract":"Transient grating spectroscopy has become a mainstay among metal and semiconductor characterization techniques. Here, we extend the technique toward the shortest achievable time scales by using tabletop high-harmonic generation of attosecond extreme ultraviolet (XUV) pulses that diffract from transient gratings generated with sub-5 fs near-infrared (NIR) pulses. We demonstrate the power of attosecond transient grating spectroscopy (ATGS) by investigating the ultrafast photoexcited dynamics in an Sb semimetal thin film. ATGS provides an element-specific, background-free signal unfettered by spectral congestion, in contrast to transient absorption spectroscopy. With ATGS measurements in Sb polycrystalline thin films, we observe the generation of coherent phonons and investigate the lattice and carrier dynamics. Among the latter processes, we extract carrier thermalization, hot carrier cooling, and electron–hole recombination, which are on the order of 20 fs, 50 fs, and 2 ps time scales, respectively. Furthermore, the simultaneous collection of transient absorption and transient grating data allows us to extract the total complex dielectric constant in the sample dynamics with a single measurement, including the real-valued refractive index, from which we are also able to investigate carrier–phonon interactions and longer-lived phonon dynamics. The outlined experimental technique expands the capabilities of transient grating spectroscopy and attosecond spectroscopies by providing a wealth of information concerning carrier and lattice dynamics with an element-selective technique at the shortest achievable time scales.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"39 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143608147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-11DOI: 10.1021/acsphotonics.4c02111
Weichao Sun, Hengzhen Cao, Jin Xie, Yuluan Xiang, Ting Chen, Jingshu Guo, Huan Li, Zejie Yu, Daoxin Dai
A silicon photonic coherent receiver with balanced Ge/Si avalanche photodiodes (APDs) is proposed and demonstrated, facilitating the realization of coherent detection with a low-power local oscillator (LO). The Ge/Si APDs used here are realized with a high responsivity for the C-band, enabling a primary responsivity of 0.84 A/W and a maximum gain of ∼289 for a −30 dBm input optical power. The present APD-based silicon photonic coherent receiver works well for 25 Gbaud Quadrature Phase-Shift Keying (QPSK) signals even with a low LO optical power of −11 dBm, and high-sensitivity data-receiving of the QPSK signals with a low optical power of −22 dBm is demonstrated successfully even without any equalization. The minimum signal power that satisfies the BER less than the hard-decision forward error correction (HD-FEC) limit is estimated to be −25 dBm by fitting the BER curve based on the equalization-free experimental results.
{"title":"Ultralow-LO-Power Silicon Photonic Coherent Receiver with Balanced Ge/Si Avalanche Photodiodes","authors":"Weichao Sun, Hengzhen Cao, Jin Xie, Yuluan Xiang, Ting Chen, Jingshu Guo, Huan Li, Zejie Yu, Daoxin Dai","doi":"10.1021/acsphotonics.4c02111","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02111","url":null,"abstract":"A silicon photonic coherent receiver with balanced Ge/Si avalanche photodiodes (APDs) is proposed and demonstrated, facilitating the realization of coherent detection with a low-power local oscillator (LO). The Ge/Si APDs used here are realized with a high responsivity for the C-band, enabling a primary responsivity of 0.84 A/W and a maximum gain of ∼289 for a −30 dBm input optical power. The present APD-based silicon photonic coherent receiver works well for 25 Gbaud Quadrature Phase-Shift Keying (QPSK) signals even with a low LO optical power of −11 dBm, and high-sensitivity data-receiving of the QPSK signals with a low optical power of −22 dBm is demonstrated successfully even without any equalization. The minimum signal power that satisfies the BER less than the hard-decision forward error correction (HD-FEC) limit is estimated to be −25 dBm by fitting the BER curve based on the equalization-free experimental results.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"31 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143590295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Light-field 3D display by super-multiviews is considered as a practical strategy to realize true 3D displays with enhanced depth cues. However, the limited space-bandwidth products pose challenges in providing an adequate number of viewpoints, while keeping a high 3D resolution. In this paper, a general strategy of “dual-view groups” is introduced into a super-multiview display, which provides 3D scenes efficiently to the binocular position. Specifically, we adopt the metagratings to modulate incident light into a dual-view group radiation pattern. Each view group is composed of super-multiviews with an angular interval of 0.45°. Such a narrow angular interval ensures that a single eye can receive multiple views simultaneously. Furthermore, by combining a multidirectional backlight module, a 15.6 in. metagrating matrix, and an LCD display, we experimentally demonstrated the proposed dual-view groups super-multiview (DVG-SMV) display can provide 3D images with correct depth cues and smooth motion parallax. The information density reaches 860.5 ppd (pixel per degree). The proposed DVG-SMV display exhibits the advantages of improved information density and accurate depth cues, which make it suitable for personal consumer electronics such as personal computers, tablets, and other applications.
{"title":"Dual-View Groups Super-multiview Display with Improved Information Density via a Large-Scale Metagrating Matrix","authors":"Jianyu Hua, Peiran Ge, Yang Li, Zhongwen Xia, Linsen Chen, Wen Qiao","doi":"10.1021/acsphotonics.4c02393","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02393","url":null,"abstract":"Light-field 3D display by super-multiviews is considered as a practical strategy to realize true 3D displays with enhanced depth cues. However, the limited space-bandwidth products pose challenges in providing an adequate number of viewpoints, while keeping a high 3D resolution. In this paper, a general strategy of “dual-view groups” is introduced into a super-multiview display, which provides 3D scenes efficiently to the binocular position. Specifically, we adopt the metagratings to modulate incident light into a dual-view group radiation pattern. Each view group is composed of super-multiviews with an angular interval of 0.45°. Such a narrow angular interval ensures that a single eye can receive multiple views simultaneously. Furthermore, by combining a multidirectional backlight module, a 15.6 in. metagrating matrix, and an LCD display, we experimentally demonstrated the proposed dual-view groups super-multiview (DVG-SMV) display can provide 3D images with correct depth cues and smooth motion parallax. The information density reaches 860.5 ppd (pixel per degree). The proposed DVG-SMV display exhibits the advantages of improved information density and accurate depth cues, which make it suitable for personal consumer electronics such as personal computers, tablets, and other applications.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"19 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143590297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-10DOI: 10.1021/acsphotonics.4c02399
Haoxiang Tian, Yi Cui, Miao Zhang, Xinrui Chen, Gaofeng Rao, Mingjie Wang, Haonan Sun, Kehan Wu, Jianwen Huang, Xianfu Wang
Neuromorphic sensors with the capability to simultaneously sense and process dynamic images show great potential for data-centric in-sensor motion perception. However, the presence of persistent background noise and redundant computational burdens limits perception accuracy and efficiency. Here, we present wavelength-sensitive bioinspired neuromorphic devices that integrate the high-level preprocessing of the human retina and ultraviolet feature extraction of the fisheye, enabling efficient image compression and background filtering capabilities to enhance motion perception. By storing dynamic image information as photoresponsivity in our nonvolatile MoTe2 homojunction, mass data can be compressed through multiplying trainable light intensity and photoresponsivity. This induces an n-fold reduction in backend computational requirements for n × n image motion perception while preserving a recognition accuracy of 100%. Furthermore, we successfully identify and track the motion of anemonefish obscured in the indistinguishable background, achieving enhanced recognition accuracy from 70% to 100%. This work showcases the substantial potential for developing intelligent vision systems with feature information extraction and high-level computational capabilities.
{"title":"Bioinspired Motion Perception Using the Wavelength-Sensitive Nonvolatile MoTe2 Homojunction","authors":"Haoxiang Tian, Yi Cui, Miao Zhang, Xinrui Chen, Gaofeng Rao, Mingjie Wang, Haonan Sun, Kehan Wu, Jianwen Huang, Xianfu Wang","doi":"10.1021/acsphotonics.4c02399","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02399","url":null,"abstract":"Neuromorphic sensors with the capability to simultaneously sense and process dynamic images show great potential for data-centric in-sensor motion perception. However, the presence of persistent background noise and redundant computational burdens limits perception accuracy and efficiency. Here, we present wavelength-sensitive bioinspired neuromorphic devices that integrate the high-level preprocessing of the human retina and ultraviolet feature extraction of the fisheye, enabling efficient image compression and background filtering capabilities to enhance motion perception. By storing dynamic image information as photoresponsivity in our nonvolatile MoTe<sub>2</sub> homojunction, mass data can be compressed through multiplying trainable light intensity and photoresponsivity. This induces an <i>n</i>-fold reduction in backend computational requirements for <i>n</i> × <i>n</i> image motion perception while preserving a recognition accuracy of 100%. Furthermore, we successfully identify and track the motion of anemonefish obscured in the indistinguishable background, achieving enhanced recognition accuracy from 70% to 100%. This work showcases the substantial potential for developing intelligent vision systems with feature information extraction and high-level computational capabilities.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"213 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143590300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-10DOI: 10.1021/acsphotonics.4c0260210.1021/acsphotonics.4c02602
Junseo Bang, Youngjin Kim, Taewon Choi, Changhyun Kim, Hyunwoo Son, Sun-Je Kim*, Yoonchan Jeong* and Byoungho Lee,
Janus metasurfaces, which manipulate light in different manners depending on illumination direction, hold potential to extend multifunctionality of meta-optics and decrease the size of integrated optical systems, simultaneously. Here, this work proposes a generalized framework for achieving bidirectional asymmetries through a cascaded meta-optics platform comprising multiple dielectric metasurfaces. Using this systematic approach, polarization-independent (scalar) asymmetric meta-holograms, polarization-dependent (vectorial) asymmetric meta-holograms, and fully generalized vectorial asymmetric modulation of forward and backward Jones matrices are proposed for the first time. In addition to unveiling advantages of separation between the two metasurfaces, it turns out that judicious use of a stochastic gradient descent algorithm enables effective optimization of the arbitrary bidirectional asymmetric meta-holograms. Our proposed method holds significance in overcoming the reciprocity-induced relationship between forward and backward Jones matrices, thereby further expanding the degrees of freedom for polarization-direction multiplexing. It is expected that the proposed work will open up new avenues in various mobile or wearable applications requiring multifunctional integrated optical systems.
{"title":"Cascaded Janus Meta-Optics: Generalized Platform for Bidirectional Asymmetric Modulation of Light","authors":"Junseo Bang, Youngjin Kim, Taewon Choi, Changhyun Kim, Hyunwoo Son, Sun-Je Kim*, Yoonchan Jeong* and Byoungho Lee, ","doi":"10.1021/acsphotonics.4c0260210.1021/acsphotonics.4c02602","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02602https://doi.org/10.1021/acsphotonics.4c02602","url":null,"abstract":"<p >Janus metasurfaces, which manipulate light in different manners depending on illumination direction, hold potential to extend multifunctionality of meta-optics and decrease the size of integrated optical systems, simultaneously. Here, this work proposes a generalized framework for achieving bidirectional asymmetries through a cascaded meta-optics platform comprising multiple dielectric metasurfaces. Using this systematic approach, polarization-independent (scalar) asymmetric meta-holograms, polarization-dependent (vectorial) asymmetric meta-holograms, and fully generalized vectorial asymmetric modulation of forward and backward Jones matrices are proposed for the first time. In addition to unveiling advantages of separation between the two metasurfaces, it turns out that judicious use of a stochastic gradient descent algorithm enables effective optimization of the arbitrary bidirectional asymmetric meta-holograms. Our proposed method holds significance in overcoming the reciprocity-induced relationship between forward and backward Jones matrices, thereby further expanding the degrees of freedom for polarization-direction multiplexing. It is expected that the proposed work will open up new avenues in various mobile or wearable applications requiring multifunctional integrated optical systems.</p>","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"12 3","pages":"1666–1675 1666–1675"},"PeriodicalIF":6.5,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143641392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-10DOI: 10.1021/acsphotonics.4c02602
Junseo Bang, Youngjin Kim, Taewon Choi, Changhyun Kim, Hyunwoo Son, Sun-Je Kim, Yoonchan Jeong, Byoungho Lee
Janus metasurfaces, which manipulate light in different manners depending on illumination direction, hold potential to extend multifunctionality of meta-optics and decrease the size of integrated optical systems, simultaneously. Here, this work proposes a generalized framework for achieving bidirectional asymmetries through a cascaded meta-optics platform comprising multiple dielectric metasurfaces. Using this systematic approach, polarization-independent (scalar) asymmetric meta-holograms, polarization-dependent (vectorial) asymmetric meta-holograms, and fully generalized vectorial asymmetric modulation of forward and backward Jones matrices are proposed for the first time. In addition to unveiling advantages of separation between the two metasurfaces, it turns out that judicious use of a stochastic gradient descent algorithm enables effective optimization of the arbitrary bidirectional asymmetric meta-holograms. Our proposed method holds significance in overcoming the reciprocity-induced relationship between forward and backward Jones matrices, thereby further expanding the degrees of freedom for polarization-direction multiplexing. It is expected that the proposed work will open up new avenues in various mobile or wearable applications requiring multifunctional integrated optical systems.
{"title":"Cascaded Janus Meta-Optics: Generalized Platform for Bidirectional Asymmetric Modulation of Light","authors":"Junseo Bang, Youngjin Kim, Taewon Choi, Changhyun Kim, Hyunwoo Son, Sun-Je Kim, Yoonchan Jeong, Byoungho Lee","doi":"10.1021/acsphotonics.4c02602","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02602","url":null,"abstract":"Janus metasurfaces, which manipulate light in different manners depending on illumination direction, hold potential to extend multifunctionality of meta-optics and decrease the size of integrated optical systems, simultaneously. Here, this work proposes a generalized framework for achieving bidirectional asymmetries through a cascaded meta-optics platform comprising multiple dielectric metasurfaces. Using this systematic approach, polarization-independent (scalar) asymmetric meta-holograms, polarization-dependent (vectorial) asymmetric meta-holograms, and fully generalized vectorial asymmetric modulation of forward and backward Jones matrices are proposed for the first time. In addition to unveiling advantages of separation between the two metasurfaces, it turns out that judicious use of a stochastic gradient descent algorithm enables effective optimization of the arbitrary bidirectional asymmetric meta-holograms. Our proposed method holds significance in overcoming the reciprocity-induced relationship between forward and backward Jones matrices, thereby further expanding the degrees of freedom for polarization-direction multiplexing. It is expected that the proposed work will open up new avenues in various mobile or wearable applications requiring multifunctional integrated optical systems.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"22 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143582542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-10DOI: 10.1021/acsphotonics.4c02542
Shamil R. Saitov, Alexander M. Smirnov, Bedil M. Saidzhonov, Roman B. Vasiliev, Alexey E. Aleksandrov, Alexey R. Tameev, Gleb O. Snigirev, Vladimir N. Mantsevich
In this paper, we experimentally investigate the effect of annealing and ligand removal on the electrical and photovoltaic properties of polycrystalline films formed from a colloidal solution of heterostructured CdSe/CdS nanoparticles in chlorobenzene using the drop-casting method. Annealing leads to a significant increase in photoconductivity, up to 4 orders of magnitude, while the band gap of the CdSe/CdS nanoplatelet film remains unchanged. Moreover, it was shown that the annealing causes a change in the dominant recombination mechanism from monomolecular to bimolecular due to an increase in charge carrier mobility. These findings directly demonstrate the possibility of creating highly photoconductive nanocrystalline films with tunable optical and electrical properties. Moreover, annealing also provides the growth of photosensitivity from approximately 0.87 to 2.75 A/W for photons with 2.12 eV energy, which is a record value for such nanocrystalline films. Considered films have the potential to significantly enhance the sensitivity of photodetectors and solar cell efficiency.
{"title":"Giant Photoconductivity of Annealed CdSe/CdS Nanoplatelet Films","authors":"Shamil R. Saitov, Alexander M. Smirnov, Bedil M. Saidzhonov, Roman B. Vasiliev, Alexey E. Aleksandrov, Alexey R. Tameev, Gleb O. Snigirev, Vladimir N. Mantsevich","doi":"10.1021/acsphotonics.4c02542","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02542","url":null,"abstract":"In this paper, we experimentally investigate the effect of annealing and ligand removal on the electrical and photovoltaic properties of polycrystalline films formed from a colloidal solution of heterostructured CdSe/CdS nanoparticles in chlorobenzene using the drop-casting method. Annealing leads to a significant increase in photoconductivity, up to 4 orders of magnitude, while the band gap of the CdSe/CdS nanoplatelet film remains unchanged. Moreover, it was shown that the annealing causes a change in the dominant recombination mechanism from monomolecular to bimolecular due to an increase in charge carrier mobility. These findings directly demonstrate the possibility of creating highly photoconductive nanocrystalline films with tunable optical and electrical properties. Moreover, annealing also provides the growth of photosensitivity from approximately 0.87 to 2.75 A/W for photons with 2.12 eV energy, which is a record value for such nanocrystalline films. Considered films have the potential to significantly enhance the sensitivity of photodetectors and solar cell efficiency.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"86 6 Suppl 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143590298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-10DOI: 10.1021/acsphotonics.4c02611
Ofer Neufeld
Lightwave control of electron dynamics and Floquet dressing in condensed matter has recently been explored with polarization-tailored laser pulses in both theory and experiments. Tailored light offers a unique approach to coherently control various phenomena in solids, from photocurrents to topology and ultrafast quantum processes such as high harmonic generation. By employing multiple carrier waves and their polarizations and phases as degrees of freedom, the extent of symmetry breaking and its impact on out-of-equilibrium phenomena can be manipulated. However, in this emerging field it remains unclear what are the key aspects of electromagnetic excitation that control responses, especially in highly nonlinear regimes. We propose a quantitative measure for the degree of time-reversal symmetry breaking (DTRSB) in a light field, which has long been well-established as an essential component for Floquet topology. We also present generalized measures for the degree of any point-group symmetry breaking in electromagnetic fields that can be employed for analysis of various experimental settings. By numerically testing the Floquet dressing of graphene with bichromatic waves that are individually linearly polarized, we show that the size of the gap opening is correlated to the DTRSB, as well as to the chirality of the electromagnetic field. Our work thus provides a roadmap for analyzing measurements and guiding experiments with tailored light control of Floquet phases and ultrafast electron dynamics.
{"title":"Degree of Time-Reversal and Dynamical Symmetry Breaking in Electromagnetic Fields and Its Connection to Floquet Engineering","authors":"Ofer Neufeld","doi":"10.1021/acsphotonics.4c02611","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02611","url":null,"abstract":"Lightwave control of electron dynamics and Floquet dressing in condensed matter has recently been explored with polarization-tailored laser pulses in both theory and experiments. Tailored light offers a unique approach to coherently control various phenomena in solids, from photocurrents to topology and ultrafast quantum processes such as high harmonic generation. By employing multiple carrier waves and their polarizations and phases as degrees of freedom, the extent of symmetry breaking and its impact on out-of-equilibrium phenomena can be manipulated. However, in this emerging field it remains unclear what are the key aspects of electromagnetic excitation that control responses, especially in highly nonlinear regimes. We propose a quantitative measure for the degree of time-reversal symmetry breaking (DTRSB) in a light field, which has long been well-established as an essential component for Floquet topology. We also present generalized measures for the degree of any point-group symmetry breaking in electromagnetic fields that can be employed for analysis of various experimental settings. By numerically testing the Floquet dressing of graphene with bichromatic waves that are individually linearly polarized, we show that the size of the gap opening is correlated to the DTRSB, as well as to the chirality of the electromagnetic field. Our work thus provides a roadmap for analyzing measurements and guiding experiments with tailored light control of Floquet phases and ultrafast electron dynamics.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"68 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143590299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-09DOI: 10.1021/acsphotonics.5c00047
Jinzhan Zhong, Houan Teng, Qiwen Zhan
Optical vortex knots and links have gained significant attention due to their fascinating spatial configurations and topological stability. However, generating vortex knots and links with high-order topological invariants has been experimentally challenging in monochromatic light. In this Article, the high-order knotted light fields are solved from braided complex zeros and decomposed into the superposition of Laguerre-Gaussian modes. We propose a noniterative mode optimization scheme to robustly generate high-order vortex knots and links in light fields with sufficient contrast. We further verified the high-quality creation of vortex topologies through experimental visual analysis. These high-order vortex topologies can be further extended to complex vector textures and applied to existing optical information coding platforms and may find analogues in other physical fields.
{"title":"Generation of High-Order Optical Vortex Knots and Links","authors":"Jinzhan Zhong, Houan Teng, Qiwen Zhan","doi":"10.1021/acsphotonics.5c00047","DOIUrl":"https://doi.org/10.1021/acsphotonics.5c00047","url":null,"abstract":"Optical vortex knots and links have gained significant attention due to their fascinating spatial configurations and topological stability. However, generating vortex knots and links with high-order topological invariants has been experimentally challenging in monochromatic light. In this Article, the high-order knotted light fields are solved from braided complex zeros and decomposed into the superposition of Laguerre-Gaussian modes. We propose a noniterative mode optimization scheme to robustly generate high-order vortex knots and links in light fields with sufficient contrast. We further verified the high-quality creation of vortex topologies through experimental visual analysis. These high-order vortex topologies can be further extended to complex vector textures and applied to existing optical information coding platforms and may find analogues in other physical fields.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"53 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143582544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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