Two-dimensional double-quantum spectroscopy: peak shapes as a sensitive probe of carrier interactions in quantum wells

摘要: We identify carrier scattering at densities below that which has previously been observed in semiconductor quantum wells. These effects are evident the peak shapes of 2D double-quantum spectra, change as a function excitation density. At high (>109 excitons/cm2), we observe untilted peaks similar to those reported previous experiments. low (<108 narrower tilted peaks. Using simple simulation, show expected spectra when inhomogeneous broadening is much larger than homogeneous broadening, and fast pure-decoherence coherence can obscure this tilt. results interactions important lower expected, “natural” hidden by typically used. Furthermore, these demonstrate analysis spectroscopy provides an incisive tool for identifying