In silicon photonics, creating dependable sources of single photons and enabling strong interactions between them has been a substantial obstacle to quantum technologies. A recent study describes a novel technique for generating indistinguishable photons from a silicon waveguide incorporating a G center.
G centers are intricate defects within silicon. They consist of two carbon atoms that have replaced silicon atoms within the crystal lattice and an additional silicon atom squeezed between them in an interstitial position. When these G centers are excited, they emit photons that hold promise for quantum networks and processors.
Traditionally, generating indistinguishable photons has necessitated complex setups incorporating cumbersome optical cavities. The method introduced in this study bypasses this requirement, offering a streamlined approach for generating indistinguishable photons within a silicon chip.
The researchers achieved this feat by meticulously controlling the placement of the G center within the silicon waveguide. This precise positioning resulted in the G center emitting photons at a specific wavelength that overlapped perfectly with a specific waveguide mode – a particular way light travels through the waveguide. This specific mode supported single photons and pairs of photons entangled, a crucial property for quantum information processing.
By meticulously tailoring the G center’s environment, the scientists enhanced the probability of the G center emitting single photons into this particular waveguide mode. It resulted in a significant generation rate of indistinguishable photons, exceeding those achievable with conventional techniques.
This research presents a groundbreaking method for generating indistinguishable photons on silicon chips. The study’s findings pave the way for the development of miniaturized and integrated quantum photonic circuits fabricated on silicon chips.
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