Superheterodyne amplification of optical and terahertz pulses in n-GaN films

The superheterodyne amplification of electromagnetic (EM) pulses of optical and terahertz ranges is investigated under the three-wave interaction with the space charge wave (SCW) in n-GaN films. SCW is amplified due to the negative differential conductivity at the frequencies f ≤ 500 GHz. The three-wave resonant interaction of two counterpropagating EM waves with SCW is considered in the waveguides based on n-GaN film onto a dielectric substrate. The amplification of EM pulses of the optical range can reach 20…40 dB at the waveguide lengths ≤100 µm.