Three conversions in a xenon fiber at UCLA
Researchers at UCLA, SLAC National Accelerator Laboratory, the University of Rochester and the University of Ottawa modelled a hollow capillary fiber filled with xenon gas. The load-bearing step is four-wave mixing: that fiber moves light between the wavelengths different quantum technologies need. The three modelled cases were conversion from 1,030 nanometres to 343, from 1,550 to 308 and from 1,550 to 516, with efficiencies of up to 28 per cent, up to 8.4 per cent and about 10.8 per cent.[1]
Phase above 0.95, and the authors' trade-off
In the calculations reported in Advanced Photonics Nexus, phase correlations stayed above 0.95 and rose above 0.99 under favourable conditions. Those correlations sit inside the UCLA-led model of a xenon-filled hollow-core fiber.[1]
The authors report a trade-off: the conditions that raise conversion efficiency also raise phase distortion. The gearbox that changes wavelength still has to keep the output shaft in time; the same conditions that push efficiency up to 28 per cent, up to 8.4 per cent and about 10.8 per cent also raise phase distortion.[1]
No direct measurement of converted quantum states in the UCLA model
The work is computational and contains no direct measurement of the converted quantum states. The authors report a trade-off: the conditions that raise conversion efficiency also raise phase distortion, so the highest conversion efficiency and the highest phase correlation compete in the same xenon-filled fiber. Another reading remains open: in the calculations reported in Advanced Photonics Nexus, phase correlations rose above 0.99 under favourable conditions that may already be settings where conversion efficiency stays modest, and a laboratory fiber might still raise conversion efficiency and phase correlation together. The binding test is a direct measurement of the converted quantum states on one of the three modelled wavelength pairs.[1]