Multimodal laser system for nonlinear Raman microspectroscopy

Methods of nonlinear optics are powerful tools for a noninvasive microscopy of biological systems and medical applications. A compact multimodal laser platform with ultrafast tunable chirped pulses is shown to provide sub-10 cm^(–1) spectral resolution in stimulated Raman spectroscopy. This makes it possible to resolve the components of a mixture and recover its quantitative composition. Furthermore, pulse-width optimization enables nonlinear Raman brain imaging: when the spectral bandwidth of laser pulses is accurately matched against the bandwidth of molecular vibrations, the coherent Raman signal is shown to be radically enhanced, resulting in higher sensitivities and higher frame rates.