Advanced photonic quantum technology relies on multiphoton interference, which requires bright sources of high-purity photons. Single-photon sources based on nonlinear parametric processes typically require lossy spectral filtering for enhancing the spectral purity of the heralded photons. Here, we implement a novel domain-engineering technique for tailoring the nonlinearity of a parametric down-conversion crystal in order to generate indistinguishable and spectrally pure photons without filtering. We create pairs of independently heralded telecom-wavelength photons with high heralding efficiency (up to 65%) and brightness (4 kHz/mW), and we demonstrate a high lower bound for the indistinguishability 98.7 0.2% and spectral purity 90.7 0.3% via two-photon interference experiments.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics