Job openings & fellowships Job openings
Select Page
Schools
From July 1, 2024 to July 3, 2024

All day

Place: ICFO Auditorium

Georgia Papadakis (ICFO)

BIO:

Georgia studied Electrical and Computer Engineering at the National Technical University of Athens. In 2011, she moved to CERN in Geneva, Switzerland, where she worked on radio frequency particle accelerators. In 2012 she joined the California Institute of Technology from where she received her PhD in Applied Physics in 2018. Georgia’s PhD work investigated light-matter interactions in nanostructures and two-dimensional materials. She did her postdoctoral studies at Stanford University during 2018-2021, in the group of S. Fan. At Stanford, Georgia worked on radiative heat transfer for renewable energy applications. Georgia joined ICFO in July 2021 as a group leader, where she works on harnessing thermal radiation for heat-to-electricity energy conversion, lighting, and sensing. She is the recipient of the National Science Foundation Graduate Research Fellowship, the Marie Curie Postdoctoral Fellowship, the Tomkat Postdoctoral Fellowship on Sustainable Energy at Stanford University, the la Caixa postdoctoral research fellowship, and the 2023 Nanophotonics Journal Early Career award.

TALK: "Far-field thermal photonics with polaritonic materials"

The blackbody spectrum peaks within the mid-infrared (IR) spectral range for near-room temperatures. In the mid-IR range, most dielectric materials exhibit pronounced phonon polariton resonances. In this talk, I will discuss means of harnessing such resonances to control the bandwidth, directionality, and state of polarization of thermal emission and radiation. First, I will demonstrate that single flakes of low-dimensional materials such as a-MoO3 or V2O5 suffice to achieve mid-IR phase retardation, based on which we have built the thinnest reported phase retarders to date [1]. Harnessing the extreme anisotropy of such flakes can also yield pronounced chiral response in the mid-IR range, which we probe in thermal emission experiments. By leveraging the ultra-low-loss of phonon polaritons supported in low-dimensional materials, for instance in hexagonal boron nitride, I will demonstrate the possibility to induce antenna-like thermal emission lobes with extreme directionality, comparable to that of grating structures [2], but realizable without any lithography [3]. I will demonstrate experimental results of such pattern-free directional thermal emission from polar materials.

A practical challenge arises in the characterization of low-dimensional exfoliated flakes at mid-IR frequencies: retrieving their dielectric properties is unattainable with standard methods like spectroscopic ellipsometry, due to the mismatch between the large size of a mid-IR beam and the small (hundreds of micrometers) size of exfoliated flakes. Previously, near-field methods have been employed for the extraction of the dielectric properties, nonetheless these are subject to considerable numerical fitting. I will introduce an approach to directly obtain the dielectric function of micros-sized-flakes using standard Fourier Transform IR Spectroscopy (FTIR) [4]. Finally, I will present the mid-IR dielectric response of another class of low-dimensional materials, transition metal dichalcogenides. Although their properties at visible frequencies are well-understood, the aforementioned practical challenge has delayed their mid-IR characterization. I will demonstrate that transition metal dichalcogenides have pronounced phonon resonances at IR frequencies that are suitable for applications in thermal photonics.
 
References:
[1] M. T. Enders, M. Sarkar, M. Giteau, A. Deeva, H. Sheinfux, M. Saremi, F. Koppens, G. T. Papadakis, Nature Communications Materials 5, 16 (2024), Deeply subwavelength mid-IR infrared phase retardation with a-MoO3 flakes
[2] J.-J. Greffet, R. Carminati, K. Joulain, J.-P. Mulet, S. Mainguy, and Y. Chen, Nature, 416 (6876) (2002), Coherent emission of light by thermal sources
[3] M. Sarkar, M. M. Enders, G. T. Papadakis, Nanophotonics 0595 (2023), Lithography-free directional control of thermal emission
[4] M. Sarkar, M. M. Enders, M. Shokooh-Saremi, K. Watanabe, T. Taniguchi, H. Sheinfux, F. Koppens, G. T. Papadakis, arxiv:2305.13994 (2023), Retrieving optical parameters of emerging van der Waals flakes,
 
 
Funding:
We acknowledge funding from “la Caixa” Foundation (ID 100010434), from the PID2021-125441OA-I00 project funded by MCIN /AEI /10.13039/501100011033/ FEDER, UE, and from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 847648. The fellowship code is LCF/BQ/PI21/11830019. This work is part of the R&D project CEX2019-000910-S, funded by MCIN/ AEI/10.13039/501100011033/ , from Fundacio Cellex, Fundacio Mir-Puig, and from Generalitat de Catalunya through the CERCA program.
Schools
From July 1, 2024 to July 3, 2024

All day

Place: ICFO Auditorium

Georgia Papadakis (ICFO)

BIO:

Georgia studied Electrical and Computer Engineering at the National Technical University of Athens. In 2011, she moved to CERN in Geneva, Switzerland, where she worked on radio frequency particle accelerators. In 2012 she joined the California Institute of Technology from where she received her PhD in Applied Physics in 2018. Georgia’s PhD work investigated light-matter interactions in nanostructures and two-dimensional materials. She did her postdoctoral studies at Stanford University during 2018-2021, in the group of S. Fan. At Stanford, Georgia worked on radiative heat transfer for renewable energy applications. Georgia joined ICFO in July 2021 as a group leader, where she works on harnessing thermal radiation for heat-to-electricity energy conversion, lighting, and sensing. She is the recipient of the National Science Foundation Graduate Research Fellowship, the Marie Curie Postdoctoral Fellowship, the Tomkat Postdoctoral Fellowship on Sustainable Energy at Stanford University, the la Caixa postdoctoral research fellowship, and the 2023 Nanophotonics Journal Early Career award.

TALK: "Far-field thermal photonics with polaritonic materials"

The blackbody spectrum peaks within the mid-infrared (IR) spectral range for near-room temperatures. In the mid-IR range, most dielectric materials exhibit pronounced phonon polariton resonances. In this talk, I will discuss means of harnessing such resonances to control the bandwidth, directionality, and state of polarization of thermal emission and radiation. First, I will demonstrate that single flakes of low-dimensional materials such as a-MoO3 or V2O5 suffice to achieve mid-IR phase retardation, based on which we have built the thinnest reported phase retarders to date [1]. Harnessing the extreme anisotropy of such flakes can also yield pronounced chiral response in the mid-IR range, which we probe in thermal emission experiments. By leveraging the ultra-low-loss of phonon polaritons supported in low-dimensional materials, for instance in hexagonal boron nitride, I will demonstrate the possibility to induce antenna-like thermal emission lobes with extreme directionality, comparable to that of grating structures [2], but realizable without any lithography [3]. I will demonstrate experimental results of such pattern-free directional thermal emission from polar materials.

A practical challenge arises in the characterization of low-dimensional exfoliated flakes at mid-IR frequencies: retrieving their dielectric properties is unattainable with standard methods like spectroscopic ellipsometry, due to the mismatch between the large size of a mid-IR beam and the small (hundreds of micrometers) size of exfoliated flakes. Previously, near-field methods have been employed for the extraction of the dielectric properties, nonetheless these are subject to considerable numerical fitting. I will introduce an approach to directly obtain the dielectric function of micros-sized-flakes using standard Fourier Transform IR Spectroscopy (FTIR) [4]. Finally, I will present the mid-IR dielectric response of another class of low-dimensional materials, transition metal dichalcogenides. Although their properties at visible frequencies are well-understood, the aforementioned practical challenge has delayed their mid-IR characterization. I will demonstrate that transition metal dichalcogenides have pronounced phonon resonances at IR frequencies that are suitable for applications in thermal photonics.
 
References:
[1] M. T. Enders, M. Sarkar, M. Giteau, A. Deeva, H. Sheinfux, M. Saremi, F. Koppens, G. T. Papadakis, Nature Communications Materials 5, 16 (2024), Deeply subwavelength mid-IR infrared phase retardation with a-MoO3 flakes
[2] J.-J. Greffet, R. Carminati, K. Joulain, J.-P. Mulet, S. Mainguy, and Y. Chen, Nature, 416 (6876) (2002), Coherent emission of light by thermal sources
[3] M. Sarkar, M. M. Enders, G. T. Papadakis, Nanophotonics 0595 (2023), Lithography-free directional control of thermal emission
[4] M. Sarkar, M. M. Enders, M. Shokooh-Saremi, K. Watanabe, T. Taniguchi, H. Sheinfux, F. Koppens, G. T. Papadakis, arxiv:2305.13994 (2023), Retrieving optical parameters of emerging van der Waals flakes,
 
 
Funding:
We acknowledge funding from “la Caixa” Foundation (ID 100010434), from the PID2021-125441OA-I00 project funded by MCIN /AEI /10.13039/501100011033/ FEDER, UE, and from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 847648. The fellowship code is LCF/BQ/PI21/11830019. This work is part of the R&D project CEX2019-000910-S, funded by MCIN/ AEI/10.13039/501100011033/ , from Fundacio Cellex, Fundacio Mir-Puig, and from Generalitat de Catalunya through the CERCA program.