Nanometer thin-film Ni-NiO-Ni diodes for mixing 28 THz CO₂-laser emissions with difference frequencies up to 176 GHz

For the first time we have demonstrated the mixing of two CO2-laser emissions near 28 THz (10.7 μm) with thin-film nanometer-scale Ni-NiO-Ni diodes (MOM, MIM) connected to integrated bow-tie antennas and integrated rhodium waveguides. Difference frequencies up to 176 GHz were observed in mixing processes up to the fifth order by the addition of microwaves generated by a Gunn oscillator. The frequencies reported are up to a factor of 30 higher than those reported previously for thin-film diodes. The current-voltage characteristics of the diodes measured at radio frequencies correspond to their nonlinearity at frequencies in the mid-infrared. The integrated bow-tie infrared antennas show almost perfect polarization with respect to the incident radiation. The ratio of the polarized versus the cross-polarized signal amplitudes is over 34 dB. These results signify the extension of millimeter-wave and microwave thin-film techniques to the infrared. © Springer-Verlag 1998.