TEP Seminar - Michał Karpiński

Spectral-temporal modes of quantum light, i.e., the complete time and frequency profiles of quantum wavepackets, are of significant importance for advanced photonic Quantum Information Processing (QIP) [1]. Specifically, integrating heterogeneous quantum components (especially solid-state emitters like quantum dots and different types of memories) into a photonic quantum network mandates precise, efficient conversion and matching of disparate spectral-temporal modes. The key challenge remains the lack of a general, low-loss method for this mode transformation. We address this important need by presenting an in-principle lossless, phase-only electro-optic methodology for the active shaping of single-photon spectra. The core mechanism involves utilizing aberration-optimized electro-optic temporal lenses [2]. I will demonstrate how this enables electro-optic spectral bandwidth modification of heralded single photons by multiple orders of magnitude [3], forming a key interface between picosecond and nanosecond quantum light pulses. The presentation will also cover the observed non-classical interference after spectral shaping, validating the coherence-preserving nature of the conversion. I will further discuss the direct application of this technique to actively modify (frequency shift) single photons generated by a solid-state quantum dot emitter [4], showcasing a promising method for deterministic spectral control of on-demand sources. These experimental achievements provide a versatile and efficient photonic interface that will contribute to the realization of scalable hybrid quantum networks and to advances in multidimensional photonic QIP.

[1]    M. Karpiński, A. O. C. Davis, F. Sośnicki, V. Thiel, B. J. Smith, “Control and measurement of quantum light pulses for quantum information science and technology,” Adv. Quantum Technol. 4, 2000150 (2021).
[2]    S. Kapoor, F. Sośnicki, M. Karpiński, " Aberration-optimized electro-optic time lens model using a tunable aperture",  APL Photonics 10, 096111 (2025).
[3]    F. Sośnicki, M. Mikołajczyk, A. Golestani, M. Karpiński, “Interface between picosecond and nanosecond quantum light pulses,” Nature Photon. 17, 761 (2023).
[4]    S. Kapoor, A. Rodek, M. Mikołajczyk, J. Szuniewicz, F. Sośnicki, T. Kazimierczuk, P. Kossacki, M. Karpiński, "Electro-optic frequency shift of single photons from a quantum dot", Nanophotonics 14, 1775 (2025)."