A nonlinear solid-state device useful for frequency conversion of electromagnetic radiation and in particular for harmonic generation, comprising a waveguiding electromagnetically distributed structure (WEDS) which includes monolithically a synthetic nonlinear material (SNM). Input radiation coupled into the WEDS is converted into a higher frequency output radiation through a constricted oscillatory motion of charge carriers and phase matched harmonic frequency generation of radiation which builds up coherently over an interaction length many time larger than the radiation wavelengths. In one embodiment, microwave radiation is converted into terahertz radiation. In other embodiments, SNM based WEDS devices are adapted for frequency mixing and parametric oscillation.