Controlling the emission spectrum of a system in a dynamic environment with external field protocols*

   Solid state quantum emitters or emitters in other dynamic environments play an essential in numerous fundamental applications from quantum information processing to quantum sensing. These applications may be hindered by spectral diffusion. The ransom drift of the emission spectrum of a quantum emitter in a dynamic environment with the surrounding fluctuations. In this talk, we consider the case of a quantum emitter subject to Gaussian fluctuations in its emission frequency as a function of time. We show that an external protocol applying a periodic sequence of pulses on the quantum emitters suppresses spectral diffusion, protecting the emission spectrum from the fluctuations in the environment. We further study an ensemble of quantum emitters, each with its own emission frequency in a Gaussian distribution of independent frequencies. The emission spectrum of this frequency is defined by the broad Gaussian distribution. However, under a periodic sequence of π-pulses, the emission spectrum of this ensemble is refocused to a central peak corresponding to the pulse carrier frequency.