Department of Physics & Astronomy

Trapping a single photon in an atomic ensemble: toward cavity QED without a cavity

February 18, 2022l Hit 1108
Date : May 11, 2022 16:00 ~
Speaker : 김윤호 (포항공과대학교 물리학과)
Professor : Prof. Dohun Kim, Prof. Sunghoon Jung
Location : 온라인 (코로나 상황에 따라 변동 가능)
The speed of light has a special place in physics and reports on the extreme dynamic control of the speed of a light pulse in an atomic medium have attracted much attention, including subluminal (down to 17 m/s) [Hau et al., Nature (1999)], superluminal [Wang et al., Nature (2000)], and even the stationary light pulse [Bajcsy et al., Nature (2003)]. The stationary light pulse (SLP) is especially of interest because the group velocity of the optical pulse in an atomic medium becomes zero while retaining the nature of the electromagnetic field, in stark contrast to light storage via electromagnetically induced transparency (EIT) in which there exist no electromagnetic waves, only coherent atomic excitations. The fact that SLP retains the nature of the electromagnetic field is significant because it could enable efficient photon-photon interaction, i.e., quantum nonlinear optics, without optical cavities, via drastically increased interaction probability between stationary photons.
 In this talk, I will first review what it means to slow down and trap the light pulse, i.e., creating the stationary light pulse, in an atomic medium, and describe my group’s efforts in realizing the single-photon stationary light pulse, including the development and characterization of the heralded single-photon sources based on cold atoms. I will finish the talk with some overly optimistic forward-looking statements on our current research directions.