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1. Classification of time-domain waveforms using a speckle-based optical reservoir computer

Author

Paudel, Uttam, Luengo-Kovac, Marta, Pilawa, Jacob, Shaw, T. Justin, and Valley, George C.

Subjects
Physics - Optics, Electrical Engineering and Systems Science - Signal Processing
Abstract

Reservoir computing is a recurrent machine learning framework that expands the dimensionality of a problem by mapping an input signal into a higher-dimension reservoir space that can capture and predict features of complex, non-linear temporal dynamics. Here, we report on a bulk optical demonstration of an analog reservoir computer using speckles generated by propagating a laser beam modulated with a spatial light modulator through a multimode waveguide. We demonstrate that the hardware can successfully perform a multivariate audio classification task performed using the Japanese vowel speakers public data set. We perform full wave optical calculations of this architecture implemented in a chip-scale platform using an SiO2 waveguide and demonstrate that it performs as well as a fully numerical implementation of reservoir computing. As all the optical components used in the experiment can be fabricated using a commercial photonic integrated circuit foundry, our result demonstrates a framework for building a scalable, chip-scale, reservoir computer capable of performing optical signal processing.

Published
2019
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2. Climate, host and geography shape insect and fungal communities of trees

Author

Franic, Iva, primary, Allan, Eric, additional, Prospero, Simone, additional, Adamson, Kalev, additional, Attorre, Fabio, additional, Auger-Rozenberg, Marie Anne, additional, Augustin, Sylvie, additional, Avtzis, Dimitrios, additional, Baert, Wim, additional, Barta, Marek, additional, Bauters, Kenneth, additional, Bellahirech, Amani, additional, Boron, Piotr, additional, Braganca, Helena, additional, Brestovanska, Tereza, additional, Brurberg, May Bente, additional, Burgess, Treena, additional, Burokiene, Daiva, additional, Cerny, Karel, additional, Cleary, Michelle, additional, Corley, Juan, additional, Coyle, David R, additional, Csoka, Gyorgy, additional, Davydenko, Kateryna, additional, de Groot, Maarten, additional, Diez, Julio Javier, additional, Dogmus Lehtijarvi, H. Tugba, additional, Drenkhan, Rein, additional, Edwards, Jacqueline, additional, Elsafy, Mohammed, additional, Eotvos, Csaba Bela, additional, Falko, Roman, additional, Fan, Jianting, additional, Feddern, Nina, additional, Furjes-Miko, Agnes, additional, Gossner, Martin, additional, Grad, Bartlomiej, additional, Hartmann, Martin, additional, Havrdova, Ludmila, additional, Horakova, Miriam Kadasi, additional, Hrabetova, Marketa, additional, Justesen, Mathias Just, additional, Kacprzyk, Magdalena, additional, Kenis, Marc, additional, Kirichenko, Natalia, additional, Kovac, Marta, additional, Kramarets, Volodymyr, additional, Lackovic, Nikola, additional, Lantschner, Maria Victoria, additional, Lazarevic, Jelena, additional, Leskiv, Marianna, additional, Li, Hongmei, additional, Madsen, Corrie Lynne, additional, Malumphy, Chris, additional, Matosevic, Dinka, additional, Matsiakh, Iryna, additional, May, Tom W, additional, Meffert, Johan, additional, Migliorini, Duccio, additional, Nikolov, Christo, additional, O Hanlon, Richard, additional, Oskay, Funda, additional, Paap, Trudy, additional, Parpan, Taras, additional, Piskur, Barbara, additional, Ravn, Hans Peter, additional, Richard, John, additional, Ronse, Anne, additional, Roques, Alain, additional, Ruffner, Beat, additional, Santini, Alberto, additional, Sivickis, Karolis, additional, Soliani, Carolina, additional, Talgo, Venche, additional, Tomoshevich, Maria, additional, Uimari, Anne, additional, Ulyshen, Michael, additional, Vettraino, Anna Maria, additional, Villari, Caterina, additional, Wang, Yongjun, additional, Witzell, Johanna, additional, Zlatkovic, Milica, additional, and Eschen, Rene, additional

Published
2023
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3. Climate, host and geography shape insect and fungal communities of trees

Author

Franic, Iva, Allan, Eric, Prospero, Simone, Adamson, Kalev, Attorre, Fabio, Auger-Rozenberg, Marie-Anne, Augustin, Sylvie, Avtzis, Dimitrios, Baert, Wim, Barta, Marek, Bauters, Kenneth, Bellahirech, Amani, Boron, Piotr, Braganca, Helena, Brestovanska, Tereza, Brurberg, May Bente, Burgess, Treena, Burokiene, Daiva, Cleary, Michelle, Corley, Juan, Coyle, David R., Csoka, Gyoergy, Cerny, Karel, Davydenko, Kateryna, de Groot, Maarten, Diez, Julio Javier, Dogmus Lehtijaervi, H. Tugba, Drenkhan, Rein, Edwards, Jacqueline, Elsafy, Mohammed, Eoetvoes, Csaba Bela, Falko, Roman, Fan, Jianting, Feddern, Nina, Fuerjes-Miko, Agnes, Gossner, Martin M., Grad, Bartlomiej, Hartmann, Martin, Havrdova, Ludmila, Horakova, Miriam Kadasi, Hrabetova, Marketa, Justesen, Mathias Just, Kacprzyk, Magdalena, Kenis, Marc, Kirichenko, Natalia, Kovac, Marta, Kramarets, Volodymyr, Lackovic, Nikola, Lantschner, Maria Victoria, Lazarevic, Jelena, Leskiv, Marianna, Li, Hongmei, Madsen, Corrie Lynne, Malumphy, Chris, Matosevic, Dinka, Matsiakh, Iryna, May, Tom W., Meffert, Johan, Migliorini, Duccio, Nikolov, Christo, O'Hanlon, Richard, Oskay, Funda, Paap, Trudy, Parpan, Taras, Piskur, Barbara, Ravn, Hans Peter, Richard, John, Ronse, Anne, Roques, Alain, Ruffner, Beat, Santini, Alberto, Sivickis, Karolis, Soliani, Carolina, Talgo, Venche, Tomoshevich, Maria, Uimari, Anne, Ulyshen, Michael, Vettraino, Anna Maria, Villari, Caterina, Wang, Yongjun, Witzell, Johanna, Zlatkovic, Milica, Eschen, Rene, Franic, Iva, Allan, Eric, Prospero, Simone, Adamson, Kalev, Attorre, Fabio, Auger-Rozenberg, Marie-Anne, Augustin, Sylvie, Avtzis, Dimitrios, Baert, Wim, Barta, Marek, Bauters, Kenneth, Bellahirech, Amani, Boron, Piotr, Braganca, Helena, Brestovanska, Tereza, Brurberg, May Bente, Burgess, Treena, Burokiene, Daiva, Cleary, Michelle, Corley, Juan, Coyle, David R., Csoka, Gyoergy, Cerny, Karel, Davydenko, Kateryna, de Groot, Maarten, Diez, Julio Javier, Dogmus Lehtijaervi, H. Tugba, Drenkhan, Rein, Edwards, Jacqueline, Elsafy, Mohammed, Eoetvoes, Csaba Bela, Falko, Roman, Fan, Jianting, Feddern, Nina, Fuerjes-Miko, Agnes, Gossner, Martin M., Grad, Bartlomiej, Hartmann, Martin, Havrdova, Ludmila, Horakova, Miriam Kadasi, Hrabetova, Marketa, Justesen, Mathias Just, Kacprzyk, Magdalena, Kenis, Marc, Kirichenko, Natalia, Kovac, Marta, Kramarets, Volodymyr, Lackovic, Nikola, Lantschner, Maria Victoria, Lazarevic, Jelena, Leskiv, Marianna, Li, Hongmei, Madsen, Corrie Lynne, Malumphy, Chris, Matosevic, Dinka, Matsiakh, Iryna, May, Tom W., Meffert, Johan, Migliorini, Duccio, Nikolov, Christo, O'Hanlon, Richard, Oskay, Funda, Paap, Trudy, Parpan, Taras, Piskur, Barbara, Ravn, Hans Peter, Richard, John, Ronse, Anne, Roques, Alain, Ruffner, Beat, Santini, Alberto, Sivickis, Karolis, Soliani, Carolina, Talgo, Venche, Tomoshevich, Maria, Uimari, Anne, Ulyshen, Michael, Vettraino, Anna Maria, Villari, Caterina, Wang, Yongjun, Witzell, Johanna, Zlatkovic, Milica, and Eschen, Rene

Abstract

Non-native pests, climate change, and their interactions are likely to alter relationships between trees and tree-associated organisms with consequences for forest health. To understand and predict such changes, factors structuring tree-associated communities need to be determined. Here, we analysed the data consisting of records of insects and fungi collected from dormant twigs from 155 tree species at 51 botanical gardens or arboreta in 32 countries. Generalized dissimilarity models revealed similar relative importance of studied climatic, host-related and geographic factors on differences in tree-associated communities. Mean annual temperature, phylogenetic distance between hosts and geographic distance between locations were the major drivers of dissimilarities. The increasing importance of high temperatures on differences in studied communities indicate that climate change could affect tree-associated organisms directly and indirectly through host range shifts. Insect and fungal communities were more similar between closely related vs. distant hosts suggesting that host range shifts may facilitate the emergence of new pests. Moreover, dissimilarities among tree-associated communities increased with geographic distance indicating that human-mediated transport may serve as a pathway of the introductions of new pests. The results of this study highlight the need to limit the establishment of tree pests and increase the resilience of forest ecosystems to changes in climate.

Published
2023
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4. Worldwide diversity of endophytic fungi and insects associated with dormant tree twigs

Author

Franic, Iva, Prospero, Simone, Adamson, Kalev, Allan, Eric, Attorre, Fabio, Auger-Rozenberg, Marie Anne, Augustin, Sylvie, Avtzis, Dimitrios, Baert, Wim, Barta, Marek, Bauters, Kenneth, Bellahirech, Amani, Boron, Piotr, Braganca, Helena, Brestovanska, Tereza, Brurberg, May Bente, Burgess, Treena, Burokiene, Daiva, Cleary, Michelle, Corley, Juan, Coyle, David R., Csoka, Gyorgy, Cerny, Karel, Davydenko, Kateryna, de Groot, Maarten, Diez, Julio Javier, Dogmus Lehtijarvi, H. Tugba, Drenkhan, Rein, Edwards, Jacqueline, Elsafy, Mohammed, Eotvos, Csaba bela, Falko, Roman, Fan, Jianting, Feddern, Nina, Furjes-Miko, Agnes, Gossner, Martin M., Grad, Bartlomiej, Hartmann, Martin, Havrdova, Ludmila, Horakova, Miriam Kadasi, Hrabetova, Marketa, Justesen, Mathias Just, Kacprzyk, Magdalena, Kenis, Marc, Kirichenko, Natalia, Kovac, Marta, Kramarets, Volodymyr, Lackovic, Nikola, Lantschner, Maria Victoria, Lazarevic, Jelena, Leskiv, Marianna, Li, Hongmei, Madsen, Corrie Lynne, Malumphy, Chris, Matosevic, Dinka, Matsiakh, Iryna, May, Tom W., Meffert, Johan, Migliorini, Duccio, Nikolov, Christo, O'Hanlon, Richard, Oskay, Funda, Paap, Trudy, Parpan, Taras, Piskur, Barbara, Ravn, Hans Peter, Richard, John, Ronse, Anne, Roques, Alain, Ruffner, Beat, Sivickis, Karolis, Soliani, Carolina, Talgo, Venche, Tomoshevich, Maria, Uimari, Anne, Ulyshen, Michael, Vettraino, Anna Maria, Villari, Caterina, Wang, Yongjun, Witzell, Johanna, Zlatkovic, Milica, Eschen, Rene, Franic, Iva, Prospero, Simone, Adamson, Kalev, Allan, Eric, Attorre, Fabio, Auger-Rozenberg, Marie Anne, Augustin, Sylvie, Avtzis, Dimitrios, Baert, Wim, Barta, Marek, Bauters, Kenneth, Bellahirech, Amani, Boron, Piotr, Braganca, Helena, Brestovanska, Tereza, Brurberg, May Bente, Burgess, Treena, Burokiene, Daiva, Cleary, Michelle, Corley, Juan, Coyle, David R., Csoka, Gyorgy, Cerny, Karel, Davydenko, Kateryna, de Groot, Maarten, Diez, Julio Javier, Dogmus Lehtijarvi, H. Tugba, Drenkhan, Rein, Edwards, Jacqueline, Elsafy, Mohammed, Eotvos, Csaba bela, Falko, Roman, Fan, Jianting, Feddern, Nina, Furjes-Miko, Agnes, Gossner, Martin M., Grad, Bartlomiej, Hartmann, Martin, Havrdova, Ludmila, Horakova, Miriam Kadasi, Hrabetova, Marketa, Justesen, Mathias Just, Kacprzyk, Magdalena, Kenis, Marc, Kirichenko, Natalia, Kovac, Marta, Kramarets, Volodymyr, Lackovic, Nikola, Lantschner, Maria Victoria, Lazarevic, Jelena, Leskiv, Marianna, Li, Hongmei, Madsen, Corrie Lynne, Malumphy, Chris, Matosevic, Dinka, Matsiakh, Iryna, May, Tom W., Meffert, Johan, Migliorini, Duccio, Nikolov, Christo, O'Hanlon, Richard, Oskay, Funda, Paap, Trudy, Parpan, Taras, Piskur, Barbara, Ravn, Hans Peter, Richard, John, Ronse, Anne, Roques, Alain, Ruffner, Beat, Sivickis, Karolis, Soliani, Carolina, Talgo, Venche, Tomoshevich, Maria, Uimari, Anne, Ulyshen, Michael, Vettraino, Anna Maria, Villari, Caterina, Wang, Yongjun, Witzell, Johanna, Zlatkovic, Milica, and Eschen, Rene

Abstract

International trade in plants and climate change are two of the main factors causing damaging tree pests (i.e. fungi and insects) to spread into new areas. To mitigate these risks, a large-scale assessment of tree-associated fungi and insects is needed. We present records of endophytic fungi and insects in twigs of 17 angiosperm and gymnosperm genera, from 51 locations in 32 countries worldwide. Endophytic fungi were characterized by high-throughput sequencing of 352 samples from 145 tree species in 28 countries. Insects were reared from 227 samples of 109 tree species in 18 countries and sorted into taxonomic orders and feeding guilds. Herbivorous insects were grouped into morphospecies and were identified using molecular and morphological approaches. This dataset reveals the diversity of tree-associated taxa, as it contains 12,721 fungal Amplicon Sequence Variants and 208 herbivorous insect morphospecies, sampled across broad geographic and climatic gradients and for many tree species. This dataset will facilitate applied and fundamental studies on the distribution of fungal endophytes and insects in trees., Datapaper

Published
2022
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5. Worldwide diversity of endophytic fungi and insects associated with dormant tree twigs

Author

Zlatkovic, Milica, Wang, Yongjun, Sivickis, Karolis, Vettraino, Anna Maria, Uimari, Anne, Franic, Iva, Witzell, Johanna, Talgo, Venche, Villari, Caterina, Ruffner, Beat, Tomoshevich, Maria, Ulyshen, Michael, Prospero, Simone, Adamson, Kalev, Allan, Eric, Attorre, Fabio, Baert, Wim, Barta, Marek, Boron, Piotr, Brestovanska, Tereza, Brurberg, May Bente, Burgess, Treena, Burokiene, Daiva, Cleary, Michelle, Coyle, David R., Cerny, Karel, de Groot, Maarten, Diez, Julio Javier, Dogmus Lehtijarvi, H. Tugba, Drenkhan, Rein, Edwards, Jacqueline, Elsafy, Mohammed, Fan, Jianting, Feddern, Nina, Gossner, Martin M., Grad, Bartlomiej, Hartmann, Martin, Havrdova, Ludmila, Horakova, Miriam Kadasi, Hrabetova, Marketa, Justesen, Mathias Just, Kacprzyk, Magdalena, Kirichenko, Natalia, Kovac, Marta, Kramarets, Volodymyr, Lazarevic, Jelena, Leskiv, Marianna, Li, Hongmei, Madsen, Corrie Lynne, Malumphy, Chris, Matosevic, Dinka, Matsiakh, Iryna, May, Tom W., Meffert, Johan, Migliorini, Duccio, Nikolov, Christo, O'Hanlon, Richard, Oskay, Funda, Paap, Trudy, Piskur, Barbara, Ravn, Hans Peter, and Richard, John

Subjects
Ecology, Forest Science, fungi
Abstract

International trade in plants and climate change are two of the main factors causing damaging tree pests (i.e. fungi and insects) to spread into new areas. To mitigate these risks, a large-scale assessment of tree-associated fungi and insects is needed. We present records of endophytic fungi and insects in twigs of 17 angiosperm and gymnosperm genera, from 51 locations in 32 countries worldwide. Endophytic fungi were characterized by high-throughput sequencing of 352 samples from 145 tree species in 28 countries. Insects were reared from 227 samples of 109 tree species in 18 countries and sorted into taxonomic orders and feeding guilds. Herbivorous insects were grouped into morphospecies and were identified using molecular and morphological approaches. This dataset reveals the diversity of tree-associated taxa, as it contains 12,721 fungal Amplicon Sequence Variants and 208 herbivorous insect morphospecies, sampled across broad geographic and climatic gradients and for many tree species. This dataset will facilitate applied and fundamental studies on the distribution of fungal endophytes and insects in trees.

Published
2022

8. Structural differences between capped GaSb nanostructures grown by Stranski-Krastanov and droplet epitaxy growth modes.

Author

DeJarld, Matt, Lifan Yan, Luengo-Kovac, Marta, Sih, Vanessa, and Millunchick, Joanna

Subjects
EPITAXY, NANOSTRUCTURES, ATOMIC force microscopy, ATOMIC layer deposition, TRANSMISSION electron microscopy
Abstract

Droplet epitaxy (DE) has emerged as an alternative to Stranski-Krastanov (SK) as a method for epitaxial nanostructure formation. We find significant structural differences of similar sized nanostructures embedded in GaAs between the two methods. Atomic force microscopy and atom probe tomography measurements reveal that uncapped and capped SK structures resemble each other. However, the DE nanostructures appear as rings topographically but are quantum dots compositionally. A GaSb wetting layer is present regardless of the growth method and shares a nearly identical Sb concentration profile. DE nanostructures are shown to have a lower Sb concentration, and transmission electron microscopy measurements reveal that they produce less strain on the capping layer. Despite significant structural differences, SK and DE nanostructures exhibit the same photoluminescence response, suggesting that the emission is from a shared feature such as the wetting layer, rather than the nanostructures. [ABSTRACT FROM AUTHOR]

Published
2017
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12. Nuclear magnetic resonance gyroscope: Developing a primary rotation sensor

Author

Bevan, Dennis, primary, Bulatowicz, Michael, additional, Clark, Philip, additional, Flicker, Julia, additional, Griffith, Robert, additional, Larsen, Michael, additional, Luengo-Kovac, Marta, additional, Pavell, James, additional, Rothballer, Ashley, additional, Sakaida, Daryl, additional, Burke, Elliot, additional, Campero, Juan, additional, Ehrsam, Brian, additional, Estrella, Steven, additional, and Morrison, Gordon, additional

Published
2018
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19. Investigation of Current Induced Spin Polarization in III-V Semiconductor Epilayers

Author

Luengo-Kovac, Marta

Subjects
semiconductor spintronics, gallium arsenide
Abstract

In the development of a semiconductor spintronics device, a thorough understanding of spin dynamics in semiconductors is necessary. In particular, electrical control of electron spins is advantageous for its compatibility with present day electronics. In this thesis, we will discuss the electrical modification of the electron g-factor, which characterizes the strength of the interaction between a spin and a magnetic field, as well as investigate electrically generated spin polarizations as a function of various material parameters. We report on the modification of the electron g-factor by an in-plane electric field in an InGaAs epilayer. We performed external magnetic field scans of the Kerr rotation of the InGaAs film in order to measure the g-factor independently of the spin-orbit fields. The g-factor increases from -0.4473(0.0001) at 0 V/cm to -0.4419( 0.0001) at 50 V/cm applied along the [110] crystal axis. A comparison of temperature and voltage dependent photoluminescence measurements indicate that minimal channel heating occurs at these voltages. Possible explanations for this g-factor modification are discussed, including an increase in the electron temperature that is independent of the lattice temperature and the modification of the donor-bound electron wave function by the electric field. The current-induced spin polarization and momentum-dependent spin-orbit field were measured in InGaAs epilayers with varying indium concentrations and silicon doping densities. Samples with higher indium concentrations and carrier concentrations and lower mobilities were found to have larger electrical spin generation efficiencies. Furthermore, current-induced spin polarization was detected in GaAs epilayers despite the absence of measurable spin-orbit fields, indicating that the spin polarization mechanism is extrinsic. Temperature-dependent measurements of the spin dephasing rates and mobilities were used to characterize the relative strengths of the intrinsic D'yakonov-Perel' and extrinsic Elliot-Yafet spin dephasing mechanisms. Proposed spin polarization mechanisms are discussed and compared with the experimental results.

Published
2017

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