二次元空間中における時間－周波数量子もつれ光子の検出と フーリエ二重性の実証

抄録

The time-frequency duality of light is the fundamental concept for ultrafast laser science and technologies. Although the 1D Fourier transform connects electric field distributions between time and frequency domains, 1D treatment is insufficient for understanding the behavior of time-frequency entangled photons. Elucidation of the Fourier duality of entangled-photon wave packets is key for further development of quantum photonics in the ultrafast regime; unfortunately, it hasn’t yet been demonstrated. Here we present the duality as it appears in the frequency spectrum and the temporal shape of the entangled- photon wave packet with two-photon coincidence measurements in the time and frequency domains to extract two-photon time-frequency distributions. We also estimate the time-bandwidth product values in 2D time-frequency space to confirm the Fourier-limited conditions of the entangled-photon wave packets and discuss the prospects of ultrafast quantum optics with time-frequency entangled photons.