Cascaded nonlinear processes during propagation of femtosecond laser pulses in nonlinear optical crystals

This paper reviews the authors recent work on cascaded nonlinear processes, revealing that cascaded nonlinear processes can lead to energy transfer between different wavelengths and spectral broadening caused by the second-order cascaded processes can provide the seed for a broadband conical emission. It further shows the relation between the input fundamental wavelength and the energy transfer effect caused by the supercontinuum generation: higher conversion efficiency is got when the input wavelength approaches the phase-matching wavelength. The significant fundamental polarization modulation caused by second order cascaded nonlinear processes is also investigated.