Multiple Quantum Frequency Conversion in Extended Interaction Structures

In 1959, E. T. Jaynes suggested that resonant, multiquantum processes could provide an efficient method of frequency conversion at high frequency and high powers. This conversion is mediated by a gas or solid composed of molecules having a strong electric-dipole absorption at a frequency /spl Omega/. Such a system can resonantly absorb energy from an electromagnetic field at all odd subharmonic of /spl Omega/. The /spl omega/ /spl ap/ /spl Omega/ /(2n + 1) subharmonic absorption is said to correspond to a 2n + 1 quantum process. The excited (driven) molecular system has electric dipole moments at all odd harmonics of the drive /spl omega/. The resonant dipole moment at a frequency (2n + 1)/spl omega/ /spl ap/ /spl Omega/ generates an electromagnetic field resulting in the frequency conversion process proposed by Jaynes. Here we report theoretical calculations and experimental observation of this multiquantum frequency conversion in a traveling-wave structure.