Single-photon pulses cannot be generated on demand, due to incompatible requirements of positive frequencies and times. Resulting states therefore contain small probabilities for multiphotons. We derive upper lower bounds the maximum fidelity realizable that approximate single-photon pulses. The have implications ultrafast optics; is low with few cycles or close onset, but increases rapidly as ...

Spatiotemporal control refers to a class of optical techniques for structuring laser pulse with coupled space-time dependent properties, including moving focal points, dynamic spot sizes, and evolving orbital angular momenta. Here we introduce the concept arbitrarily structured (ASTRL) pulses which generalizes these techniques. The ASTRL formalism employs superposition prescribed create desired...