Rectangular and triangular two-dimensional spectra.

<p>(<b>A</b>) Example of a conventional array of excitation/emission wavelengths used for acquisition of two-dimensional fluorescence spectra. The diagonal (λ_em = λ_ex) is shown with the open symbols. The conventional 1D emission spectrum is a horizontal set of points for each excitation wavelength to the right of the open symbol. Correspondingly, the 1D excitation spectrum is a vertical set of points below the open symbol. (<b>B</b>) The triangular array of excitation/emission wavelengths where the emission ranges always begin at a greater wavelength than the excitation wavelength in each row. The specific 100 nm increment in this figure is chosen solely for clarity of presentation.