Optical photons are ideal carriers of quantum information. But to work together in a quantum computer or network, they need to have the same color — or frequency — and bandwidth. Changing a photon’s frequency requires altering its energy, which is particularly challenging on integrated photonic chips.
Recently, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) developed an integrated electro-optic modulator that can efficiently change the frequency and bandwidth of single photons. The device could be used for more advanced quantum computing and quantum networks.
Converting a photon from one color to another is usually done by sending the photon into a crystal with a strong laser shining through it, a process that tends to be inefficient and noisy. Phase modulation, in which photon wave’s oscillation is accelerated or slowed down to change the photon’s frequency, offers a more efficient method, but the device required for such a process, an electro-optic phase modulator, has proven difficult to integrate on a chip.
One material may be uniquely suited for such an application — thin-film lithium niobate.
The research is published in Light: Science & Applications.
Reference : Di Zhu, Changchen Chen, Mengjie Yu, Linbo Shao, Yaowen Hu, C. J. Xin, Matthew Yeh, Soumya Ghosh, Lingyan He, Christian Reimer, Neil Sinclair, Franco N. C. Wong, Mian Zhang, Marko Lončar. Spectral control of nonclassical light pulses using an integrated thin-film lithium niobate modulator. Light: Science & Applications, 2022; 11 (1) DOI: 10.1038/s41377-022-01029-7
