Compact design for two-dimensional electronic spectroscopy

We present a passively phase-stabilized two-dimensional electronic spectroscopy (2DES) with a compact size, and the ease of implementation and maintenance. Our design relies on a mask beam-splitter with four holes to form non-collinear box geometry, and a homebuilt stacked retroreflector, which introduces the phase-locked pulse sequence, remedying the instability of commonly used translation stages. The minimized size of the setup suppresses the influences of optical path-length fluctuations during measurements, improving the phase stability and precise timing of pulse sequences. In our 2DES, only few conventional optical components are used, which make this sophisticated instrumentation convenient to establish and particularly easy to conduct alignment. In data analysis, the self-referencing spectral interferometry (SRSI) method is first introduced to extract the complex-valued signal from spectral interferometry in 2DES. The alternative algorithm achieves the improvement of the signal-to-noise ratio (SNR) and considerable reduction of data acquisition time. The new setup is suitable over a tunable range of spectroscopic wavelength, from ultraviolet (UV) to the near-infrared (NIR) regime, and for ultra-broadband bandwidth, few-cycle laser pulses.