Seminarium Optyczne

There is growing interest in interfacing diverse quantum systems into a hybrid quantum network. However, their implementation is bottlenecked by incompatible timescales and spectral bandwidths, necessitating coherent manipulation of bandwidth and central wavelengths. Spectral bandwidth manipulation and spectral tuning of heralded single photons from spontaneous parametric down-conversion have been demonstrated using electro-optic phase modulation (EOPM) and dispersive propagation [1]. In this talk, I will introduce a new analytical model that significantly improves the foundational performance of sinusoidal time lenses [2]. Additionally, I will discuss the spectral tuning of photons emitted by a solid-state single-photon source using electro-optic modulation [3].I will first introduce the foundational concept of spectral bandwidth manipulation and frequency conversion using the optical space-time analogy, showing how a time lens based on electro-optic phase modulation can perform the temporal equivalent of spatial focusing, thereby compressing or expanding the spectral bandwidth. I will present a new analytical tunable-aperture model that significantly reduces temporal aberrations in conventional sinusoidal time lenses [2]. Then I will demonstrate central-wavelength tuning of quantum light using serrodyne modulation (a sawtooth waveform) to precisely shift the frequency of single photons emitted by a quantum dot by up to ±5.25 GHz. We experimentally confirm that this electro-optic technique preserves the single-photon number purity and indistinguishability between subsequent emitted photons [3]. This work establishes EOPM as a versatile tool for quantum interface engineering, with the potential to scale through future integration onto integrated photonics platforms.[1] M. Karpiński et al., Adv. Quantum Technol. 4, 2000150 (2021).[2] S. Kapoor et al., APL Photonics 10, 096111 (2025).[3] S. Kapoor, A. Rodek et al., Nanophotonics 14, 1775–1782 (2025).