By customizing the nonlinear optical properties of materials, we can manipulate the structure of light as it passes through. This allows us to manipulate the light to emphasize quantum properties like entanglement or squeezing for quantum computing or quantum-enhanced sensing applications.

Nonlinear materials can be used to combine or split photons. Parametric down-conversion is a common example where incoming photons are split into two entangled outgoing photons with half the energy. We are developing techniques for generalizing this idea to generate entangled photons with different energies (color entanglement). Run in reverse, this process can be used to merge lots of low-energy photons into high energy ones, producing a beam of directed energy.

The possibility of entangling colors allows one to conceive of using photons for quantum computing. This generalizes the idea of a two-state qubit to a multi-state qudit, increasing the potential bandwidth of the device. Photons have the additional advantage of working at room temperature, removing the need for the costly cooling apparatus associated with many other quantum computing platforms.