We present analytic and numerical studies of sum frequency generation (SFG) and difference frequency generation (DFG) for broadband input fields. The conversion efficiency of SFG and DFG for broadband input fields are affected by amplitude modulation of the input fields, but frequency modulation does not affect conversion efficiency. Optimal SFG quantum conversion efficiency approaches that of second harmonic generation only if the quantum fluence (total number of photons) in the two input beams are equal, whereas optimal DFG quantum conversion efficiency occurs when the number of photons of frequency ω-2$/ is small but yet sufficient for significant stimulation. A recently developed method for obtaining efficient SFG for multimode input fields is theoretically analyzed. The method employs an arrangement with two or more non linear mixing crystals and a time delay line between the crystals that delays one of the fundamental fields relative to the other. We show that the conversion efficiency in the second crystal depends on the cross correlation function of the two fundamental fields upon leaving the first nonlinear crystal.
|Number of pages||18|
|Journal||Molecular Crystals and Liquid Crystals Science and Technology Section B: Nonlinear Optics|
|State||Published - 1 Jan 1995|