DPSS yellow‐green 561‐nm lasers for improved fluorochrome detection by flow cytometry

Blue‐green 488‐nm laser sources are widespread in flow cytometry but suffer some drawbacks for cell analysis, including their excitation of endogenous proteins (resulting in high cellular autofluorescence) and their less‐than‐optimal coincidence with the excitation maxima of commonly used fluorochromes, including the phycoerythrins (PE). Longer wavelength lasers such as green helium–neons and, more recently, diode‐pumped solid state (DPSS) 532‐nm sources have previously been employed to overcome these difficulties and improve overall sensitivity for PE. In this study, we evaluate an even longer wavelength DPSS 561‐nm for its ability to improve PE and DsRed fluorescent protein detection sensitivity.