The coherent laser light in different spectral regions is needed for the applications in Science, Medicine and Technology. The standard laser sources normally have a special wavelength or a very limited tunablity. Nonlinear Optics has provided a solution for these problems via various nonlinear interaction schemes. By appropriate application of different second and third order nonlinear interactions, it is possible to cover a wide area across the whole spectral range from Vacuum UV to Mid-infrared. Because of the very small values of the nonlinear interaction coefficients (10E-12 and 10E-24 for second and third order nonlinearities, respectively) higher intensities of ultrashort pulses give them the priority for the efficient interactions. In this talk we will try to present the results of the successful application of different nonlinear interactions using femtosecond pulses for the efficient generation of tunable ultrashort pulses across the different parts of the spectrum.
