School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA.
Phys Rev Lett. 2011 Nov 4;107(19):193902. doi: 10.1103/PhysRevLett.107.193902. Epub 2011 Nov 3.
We demonstrate 25% all-optical modulation with <20 photons, i.e., a few attojoules of energy, using nondegenerate two-photon absorption in rubidium atoms confined to a hollow-core photonic band-gap fiber. An attenuation of up to 3 dB is induced on an optical field with a switching energy density of less than one photon per (λ(2)/2π). We show that the temporal response of the system is determined by the 5-ns transit time of the atoms across the optical mode of the fiber, which results in a modulation bandwidth up to 50 MHz.
我们演示了在囚禁于空心光纤的铷原子中非简并双光子吸收作用下，只需 20 个光子（即几个飞焦耳的能量）即可实现 25%的全光调制。在开关能量密度小于每个（λ(2)/2π）光子的条件下，我们在光场中感应出了高达 3dB 的衰减。我们表明，系统的时间响应由原子穿过光纤光模的 5ns 渡越时间决定，这导致调制带宽高达 50MHz。
