IEM Distinguished Lecturers Seminar: Ultracompact nonlinear platforms based on layered semiconductors for phase-matched up- and down-conversion
***Coffee and cookies will be served at 13:00 in the hall of BM 5202***
Abstract
Nonlinear optics lies at the heart of classical and quantum light generation. The miniaturization and on-chip integration paradigm, which has dominated the world of electronics, is now shifting to the field of photonics, with the development of all-optical integrated circuits, essential for new photonic technologies required to address rising demands for fast and energy-efficient quantum processing. The miniaturization problem manifests as a stubborn trade-off between frequency conversion efficiency and size.
While 2D materials, such as transition metal dichalcogenides (TMDs), hold great promise thanks to their large nonlinearity (χ(2)), their stability in ambient conditions, their flexibility and mechanical strength, and easy system integration, monolayer-thick sheets provide low overall conversion efficiency (~10-10) due to near-infinitesimal path lengths.
Here we realize periodically poled transition metal dichalcogenides (PPTMDs), using 3R-MoS2. Due to its large nonlinearity, we achieve macroscopic frequency conversion efficiency (0.01%-0.1%) over a microscopic thickness of only 3μm (just three poling periods), i.e., 108 times more efficient than a monolayer TMD. Further, we report the generation of entangled photon pairs at telecom wavelengths via quasi-phase-matched spontaneous parametric down-conversion (SPDC) at the key 1550 nm telecom wavelength, reaching a maximum coincidence-to-accidental-ratio (CAR) of 638 ± 75, thus outperforming any existing van der Waals-based SPDC source by nearly 2 orders of magnitude.
This research opens the new and unexplored field of phase-matched nonlinear optics with microscopic van der Waals crystals. As on-chip integrable, programmable, microscopic, entangled photon sources, PPTMDs finally unlock new applications that require simple, ultracompact technologies for integrated quantum circuitry and sensing.
Bio
Chiara Trovatello is a Marie Skłodowska-Curie Global Fellow at Columbia University and Politecnico di Milano. Her research activity focuses on ultrafast spectroscopy, nonlinear optics and quantum optics of low-dimensional materials, e.g., 2D semiconductors. She has published >25 papers, has delivered >30 invited and contributed talks at leading conferences and institutions, and has been part of the organizing committee of international conferences, e.g., MRS, CLEO.
Among her prizes and grants, she has been awarded the Marie Skłodowska-Curie RISE Fellowship (2019), the Marie Skłodowska-Curie Global Fellowship (2022), the 2022 Bernard J. Couillaud Prize, the 2023 Young Investigator Bruno Touschek Award, the 2024 L’Oréal-UNESCO for Women in Science Prize, the 2024 Blavatnik Regional Finalist Award and the 2024 Optica Foundation Challenge Award.
Chiara Trovatello was the founder and the former president of the Optica Chapter of Milan and in 2024 she has been awarded the lifetime title of Optica Ambassador. Beyond research, she passionately advocates for open science, ethical research, equal representation and opportunities in STEM.
Abstract
Nonlinear optics lies at the heart of classical and quantum light generation. The miniaturization and on-chip integration paradigm, which has dominated the world of electronics, is now shifting to the field of photonics, with the development of all-optical integrated circuits, essential for new photonic technologies required to address rising demands for fast and energy-efficient quantum processing. The miniaturization problem manifests as a stubborn trade-off between frequency conversion efficiency and size.
While 2D materials, such as transition metal dichalcogenides (TMDs), hold great promise thanks to their large nonlinearity (χ(2)), their stability in ambient conditions, their flexibility and mechanical strength, and easy system integration, monolayer-thick sheets provide low overall conversion efficiency (~10-10) due to near-infinitesimal path lengths.
Here we realize periodically poled transition metal dichalcogenides (PPTMDs), using 3R-MoS2. Due to its large nonlinearity, we achieve macroscopic frequency conversion efficiency (0.01%-0.1%) over a microscopic thickness of only 3μm (just three poling periods), i.e., 108 times more efficient than a monolayer TMD. Further, we report the generation of entangled photon pairs at telecom wavelengths via quasi-phase-matched spontaneous parametric down-conversion (SPDC) at the key 1550 nm telecom wavelength, reaching a maximum coincidence-to-accidental-ratio (CAR) of 638 ± 75, thus outperforming any existing van der Waals-based SPDC source by nearly 2 orders of magnitude.
This research opens the new and unexplored field of phase-matched nonlinear optics with microscopic van der Waals crystals. As on-chip integrable, programmable, microscopic, entangled photon sources, PPTMDs finally unlock new applications that require simple, ultracompact technologies for integrated quantum circuitry and sensing.
Bio
Chiara Trovatello is a Marie Skłodowska-Curie Global Fellow at Columbia University and Politecnico di Milano. Her research activity focuses on ultrafast spectroscopy, nonlinear optics and quantum optics of low-dimensional materials, e.g., 2D semiconductors. She has published >25 papers, has delivered >30 invited and contributed talks at leading conferences and institutions, and has been part of the organizing committee of international conferences, e.g., MRS, CLEO.
Among her prizes and grants, she has been awarded the Marie Skłodowska-Curie RISE Fellowship (2019), the Marie Skłodowska-Curie Global Fellowship (2022), the 2022 Bernard J. Couillaud Prize, the 2023 Young Investigator Bruno Touschek Award, the 2024 L’Oréal-UNESCO for Women in Science Prize, the 2024 Blavatnik Regional Finalist Award and the 2024 Optica Foundation Challenge Award.
Chiara Trovatello was the founder and the former president of the Optica Chapter of Milan and in 2024 she has been awarded the lifetime title of Optica Ambassador. Beyond research, she passionately advocates for open science, ethical research, equal representation and opportunities in STEM.
Practical information
- General public
- Free