Extracting Entangled Pulses from Continuous-Wave Photon Sources

Squeezed light is a versatile resource for optical quantum computing, sensing, and communication. However, the light source usually requires complicated optimization when generating a pulse with the desired shape, resulting in inflexible state preparation. In our work, we present a protocol for extracting pure squeezed states with arbitrary pulse shape by "cutting out" the desired output from any source of squeezed photons. We achieve this by using the nullifier formalism to characterize the output modes, and show that heterodyne detections on selective temporal modes will disentangle the desired state from the remaining undesired modes. Our method can be used to deterministically prepare single- and two-mode squeezed state in any shape from a continuum source, and projectively measure arbitrary states in any pulse onto squeezed bases.