A recent Caltech News article profiles some research in squeezed states of light. And why that is useful.
• Wiki > Squeezed coherent state
• Wiki > Squeezed states of light
(quote) In quantum physics, light is in a squeezed state if its electric field strength Ԑ for some phases ϑ has a quantum uncertainty smaller than that of a coherent state.
• Caltech > News > “New Photonic Chip “Squeezes” More out of Light” (September 15, 2022) – The paper describing the research, titled, “Few-cycle vacuum squeezing in nanophotonics,” appears in the September 15 issue of the journal Science.
(quote) The chip is based on lithium niobite, a salt whose crystals have many applications in optics. It generates what are known as squeezed states of light on one side of the chip and measures them on the other side. A squeezed state of light is, to put it very simply, light when it has been made less “noisy” on the quantum level. Squeezed states of light have recently been used to increase the sensitivity of LIGO, the observatory that uses laser beams to detect gravitational waves. That same less-noisy state of light is important if you are going to process data with light-based quantum devices.