From slowing down atoms by photons to slowing down photons by atoms

Gourab Pal

Laser cooling is a widely used popular tool to slow down atoms from hundreds of meters per second to few centimetres per second, enabling physicist to capture various interesting phenomena. In QuMix lab, we have slowed down bosonic Sodium and Potassium atoms [1] using photons from a coherent source (a laser), to few cm/s to study different kinds of collisions and interaction regimes. On the other hand, photons can be slowed down too. Utilizing the destructive interference between two excitation pathways, and creating a coherent EIT medium [2], group velocity of light can be made to crawling speed (few m/s). I will show results of such slow light that we produced in the lab which is 104 order slower than the velocity of light in free space.

[1] Sagar Sutradhar et.al, https://doi.org/10.1063/5.0154985

[2] Gourab Pal, Saptarishi Chaudhuri, (Preprint)