title: Two-dimensional electronic spectroscopy with double modulation lock-in detection: enhancement of sensitivity and noise resistance.
abstract: In many potential applications of two-dimensional (2D) electronic spectroscopy the excitation energies per pulse are strictly limited, while the samples are strongly scattering. We demonstrate a technique, based on double-modulation of incident laser beams with mechanical choppers, which can be implemented in almost any non-collinear four wave mixing scheme including 2D spectroscopy setup. The technique virtually eliminates artifacts or "ghost" signals in 2D spectra, which arise due to scattering and accumulation of long-lived species. To illustrate the advantages of the technique, we show a comparison of porphyrin J-aggregate 2D spectra obtained with different methods following by discussion.
authors: Department of Chemical Physics, Lund University, Lund, Sweden.
authors: Ramūnas
authors: R
authors: Augulis
authors: Donatas
authors: D
authors: Zigmantas
mesh_terms: D016477:Artifacts; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013057:Spectrum Analysis / Q000295:instrumentation*