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Efficient Hotspot Switching in Plasmonic Nanoantennas using Phase-shaped Laser Pulses controlled by Neural Networks
Authors:
Alberto Comin,
Achim Hartschuh
Abstract:
We present a novel procedure for manipulating the near-field of plasmonic nanoantennas using neural network-controlled laser pulse-shaping. As model systems we numerically studied the spatial distribution of the second harmonic response of L-shaped nanoantennas illuminated by broadband laser pulses. We first show that a trained neural network can be used to predict the relative intensity of the se…
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We present a novel procedure for manipulating the near-field of plasmonic nanoantennas using neural network-controlled laser pulse-shaping. As model systems we numerically studied the spatial distribution of the second harmonic response of L-shaped nanoantennas illuminated by broadband laser pulses. We first show that a trained neural network can be used to predict the relative intensity of the second-harmonic hotspots of the nanoantenna for a given spectral phase and that it can be employed to deterministically switch individual hotspots on and off on sub-diffraction length scale by shaping the spectral phase of the laser pulse. We then demonstrate that a neural network trained on a $90~\mathrm{nm} \times 150~\mathrm{nm}$ nano-L can in addition efficiently predict the hotspot intensities in an antenna with different aspect ratio after minimal further training for varying spectral phases. These results could lead to novel applications of machine-learning and optical control to nanoantennas and nanophotonics components.
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Submitted 5 October, 2018;
originally announced October 2018.
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Microscopic view on the ultrafast photoluminescence from photo-excited graphene
Authors:
Torben Winzer,
Richard Ciesielski,
Matthias Handloser,
Alberto Comin,
Achim Hartschuh,
Ermin Malic
Abstract:
We present a joint theory-experiment study on ultrafast photoluminescence from photoexcited graphene. Based on a microscopic theory, we reveal two distinct mechanisms behind the occurring photoluminescence: Besides the well-known incoherent contribution driven by non-equilibrium carrier occupations, we found a coherent part that spectrally shifts with the excitation energy. In our experiments, we…
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We present a joint theory-experiment study on ultrafast photoluminescence from photoexcited graphene. Based on a microscopic theory, we reveal two distinct mechanisms behind the occurring photoluminescence: Besides the well-known incoherent contribution driven by non-equilibrium carrier occupations, we found a coherent part that spectrally shifts with the excitation energy. In our experiments, we demonstrate for the first time the predicted appearance and spectral shift of the coherent photoluminescence.
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Submitted 3 November, 2014;
originally announced November 2014.
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Plasmonics in heavily-doped semiconductor nanocrystals
Authors:
Francesco Scotognella,
Giuseppe Della Valle,
Ajay Ram Srimath Kandada,
Margherita Zavelani-Rossi,
Alberto Comin,
Stefano Longhi,
Liberato Manna,
Guglielmo Lanzani,
Francesco Tassone
Abstract:
Heavily-doped semiconductor nanocrystals characterized by a tunable plasmonic band have been gaining increasing attention recently. Herein, we introduce this type of materials focusing on their structural and photo physical properties. Beside their continuous-wave plasmonic response, depicted both theoretically and experimentally, we also review recent results on their transient, ultrafast respons…
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Heavily-doped semiconductor nanocrystals characterized by a tunable plasmonic band have been gaining increasing attention recently. Herein, we introduce this type of materials focusing on their structural and photo physical properties. Beside their continuous-wave plasmonic response, depicted both theoretically and experimentally, we also review recent results on their transient, ultrafast response. This was successfully interpreted by adapting models of the ultrafast response of gold nanoparticles.
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Submitted 5 June, 2013;
originally announced June 2013.