In a paper published in Nature’s NPJ Quantum Information (“Multiphoton quantum-state engineering using conditional measurements”), Omar Magaña-Loaiza, assistant professor in the Louisiana State University (LSU) Department of Physics & Astronomy, and his team of researchers describe a noteworthy step forward in the quantum manipulation and control of light, which has far-reaching quantum technology applications in imaging, simulation, metrology, computation, communication, and cryptography, among other areas.

At the quantum level, light remains difficult to control for engineering purposes.

“If we’re able to control photon fluctuations and associated noise,” Magaña-Loaiza said. “Then, we can make more precise measurements. This technology is new and will change our field.”

Physicists all over the world are racing to develop techniques to preserve light’s quantum properties at large enough scales for practical purposes. While physicists can so far control the quantum properties of single photons and pairs of photons, leading to powerful applications through entanglement and “heralding” (wherein knowledge of one photon gives relatively certain knowledge about another, not-yet-detected photon), Magaña-Loaiza’s team successfully demonstrated a method to generate groups of photons with these same powerful properties–known as multiphoton states.

By subtracting out some photons, Magaña-Loaiza said, “We can reshape the form of the wavepacket and artificially increase the number of photons in it.”

Image Credit:  Elsa Hahne/ORED