Spectral Tailoring of Inhomogeneous Optical Response Using Two-Dimensional Coherent Spectroscopy

Abstract: Controlling the coherent optical response of inhomogeneous ensembles is a key challenge in advancing light-matter interaction engineering. We present a comparative study of two spectral tailoring approaches using two-dimensional coherent spectroscopy (2DCS): the prepulse and double-pulse (DP) methods. In the prepulse scheme, a high-intensity pulse induces Rabi oscillations, modulating the 2D spectral amplitude and lineshape when its spectral bandwidth matches the ensemble full width at half maximum (FWHM). To overcome this limitation, the DP method employs variable inter-pulse delay to generate predetermined periodic spectral modulation without bandwidth constraints. Moreover, tuning the relative phase between DP pulses allows selective switching of frequency components, enabling controlled enhancement or suppression of distinct spectral features. These observations highlight that, while the prepulse approach is constrained by spectral bandwidth, the DP method provides a more versatile and reliable route to manipulate the coherent optical response of inhomogeneous ensembles. We are hoping these findings might stimulate further research in optical switching and coherent storage for quantum memory devices using inhomogeneous ensembles.