Nitrogen-rich silicon nitride proves viable for future use as a quantum photonics platform

Isolating and manipulating single atom-like systems in the solid state has led to many advances in quantum engineering. When it comes to constructing efficient photonic interfaces, however, finding the right material platform remains a bottleneck for scaling up solid state quantum systems. Nitrogen-rich silicon nitrides have shown promise for these uses due to their low auto-fluorescence at visible wavelengths. New work points to a path forward for building integrated photonic platforms using solid state emitters.

Smith et al. have demonstrated the viability of nitrogen-rich silicon nitride for use as a quantum photonics platform. By growing low-noise film on top of localized single emitters, the group has been able to show that nitrogen vacancy centers within nanodiamonds preserve both their quantum optical and spin properties post-encapsulation. The work marks a new use for silicon nitride, which has already been demonstrated in other high-performance photonics devices.

“For the first time, we have demonstrated how to integrate single atom-like systems that have coherent memories into a chip-scale photonic material such as silicon nitride,” said author Joe Smith.

This work moves away from finding the right type of atom-like emitters to a systems-level approach with the focus on integrating many atom-like emitters in a chip-scale photonics platform. By returning to the same emitters and measuring single photon emission, the low noise nitride and its resulting hybrid materials platform have proven compatible with quantum information processing.

Now that the group has demonstrated the hybrid material, they next look to demonstrate its use in devices such as photonic cavities. The goal is to link arrays of atom-like systems using the platform, which will also allow them to obtain larger-scale statistics about the material.

Source: “Single photon emission and single spin coherence of a nitrogen vacancy centre encapsulated in silicon nitride,” by Joe Smith, Jorge Monroy-Ruz, John G. Rarity, and Krishna C. Balram, Applied Physics Letters (2019). The article can be accessed at https://doi.org/10.1063/5.0002709 .