1 College of Electric Power, North China University of Water Resources and Electric Power, Zhengzhou 450045, China; 2 College of Surveying and Geo-informatics, North China University of Water Resources and Electric Power, Zhengzhou 450045, China; 3 College of Precision Instrument and Opto-electronics Engineering, Institute of Laser and Opto-electronics, Tianjin University, Tianjin 300072, China
Abstract A novel scheme for high-efficiency terahertz (THz) wave generation based on optimized cascaded difference frequency generation (OCDFG) with planar waveguide is presented. The phase mismatches of each-order cascaded difference frequency generation (CDFG) are modulated by changing the thickness of the waveguide, resulting in a decrement of phase mismatches in cascaded Stokes processes and an increment of phase mismatches in cascaded anti-Stokes processes simultaneously. The modulated phase mismatches enhance the cascaded Stokes processes and suppress the cascaded anti-Stokes processes simultaneously, yielding energy conversion efficiencies over 25% from optical wave to THz wave at 100 K.
(Frequency conversion; harmonic generation, including higher-order harmonic generation)
Fund: Project supported by the National Natural Science Foundation of China (Grant Nos. 61735010, 31671580, and 61601183), Natural Science Foundation of Henan Province, China (Grant No. 162300410190), and Program for Science & Technology Innovation Talents in Universities of Henan Province, China (Grant No. 18HASTIT023).
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