Fiber optical parametric frequency conversion: Alignment and maintenance free all-fiber laser concept for CARS microscopy

We present the development and experimental demonstration of a parametric all-fiber laser source for CARS microscopy. Since the pump and Stokes wavelengths are generated by four-wave-mixing, both pulses are emitted from a single fiber end with intrinsic synchronization. The generated wavelength pair around 780 nm and 1030 nm was used to probe the aromatic CH-stretch vibrational resonance of toluene at 3050 cm^-1. Reproduction of the CARS resonance bandshape by spectral tuning as well as microscopic imaging within the aromatic CH-stretching region demonstrates the CARS capabilities of the laser.