Spontanous Parametric Down-Conversion

The advancement of versatile photonic sources plays a pivotal role in driving the progress of photonic quantum technologies. Our research interests cover the development of photonic sources tailored for diverse requirements in quantum optics investigations. Specifically, we establish the ultra-bright and high-fidelity EPR sources using spontaneous parametric down-conversion (SPDC), for conducting high-demanding quantum experiments such as genuine multipartite nonlocality within quantum networks and related tasks in adversarial scenarios. Additionally, our photonic platform includes solid-state quantum dot sources for deterministic single photon generation essential for scalable quantum computation and exploration of spin-photon entanglement or interactions. We are also exploring cavity-enhanced SPDC to produce narrowband photons with ultra-long coherent lengths, serving as interface for atomic systems and facilitating the global quantum network involving quantum memories, as well as promising investigations in cavity quantum electrodynamics (CQED).

Publications (selected)

Photonic Source of Heralded Greenberger-Horne-Zeilinger States
H. Cao, L. M. Hansen, F. Giorgino, L. Carosini, P. Zahálka, F. Zilk, J. Loredo, P. Walther
Physical Review Letters 132, 130604 (2024).

Cross-verification of independent quantum devices
C. Greganti, T.  Demarie, M. Ringbauer, J. Jones, V. Saggio, I. Calafell, L. A. Rozema, A. Erhard, M. Meth, L. Postler, R. Stricker, P. Schindler, R. Blatt, T. Monz, P. Walther, J. Fitzsimons
Physical Review X 11, 031049 (2021).

Experimental few-copy multipartite entanglement detection
S. Valeria, A. Dimić, C. Greganti, L. Rozema, P. Walther, B. Dakić
Nature physics 15, 935 (2019).

Novel single-mode narrow-band photon source of high brightness tuned to cesium D2 line.
M. Amir, F. Massa, P. Walther.
APL Photonics 4 (2019).

Tuning single-photon sources for telecom multi-photon experiments.
C. Greganti, P. Schiansky, I. Calafell, L. Procopio, L. A. Rozema, P. Walther.
Optics express 26, 3286 (2018).