Elohim Becerra Chavez recently published Quantum measurements: surpassing conventional sensitivity limits at low powers in Nature Partner Journals
Light has intrinsic quantum noise, which limits how well we can measure it, especially at low powers, and bounds how much information we can communicate. A team led by F. Elohim Becerra at the University of New Mexico demonstrated optimized measurements for light pulses with different phases at low powers, such as those used in coherent optical communication. These optimized measurements can surpass the ultimate sensitivity limits of ideal conventional detectors, even in the presence of loss and noise encountered in realistic situations. The measurements are based on combining the input pulse with a reference field, and counting single photons in a fraction of the pulse. By analyzing the detection outcome, the reference field can be optimized to enhance the measurement’s sensitivity. Optimized measurements at low powers may lead to more-efficient optical communication in realistic environments.
The full article can be found online at npj Quantum Information 3, Article number: 43 (2017) .