Two-dimensional electronic spectroscopy with double modulation lock-in detection: enhancement of sensitivity and noise resistance

• DOI: 10.1364/oe.19.013126
• Publication Date: 2011-06-22T18:54:04Z
• Authors: Ramūnas Augulis; Donatas Zigmantas
• Keywords: Equipment Failure Analysis; Lasers; Spectrum Analysis; 0103 physical sciences; Signal Processing, Computer-Assisted; Equipment Design; Micro-Electrical-Mechanical Systems; Artifacts; 01 natural sciences

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.