Research On Terahertz Wave Devices Based On 2-D Photonic Crystals

In recent years,terahertz wave technology is during a period of fast development.Due to the superior characteristics of photonic crystal,the combine of the terahertz wave and photonic crystal has provide a new way and solution to the design of terahertz wave function device.Using the theory of photonic crystal coupling,multimode interference and self-imaging phenomenon,four terahertz wave device have been designed in this thesis.The main research contents are summarized as follows:1.Compact terahertz wave polarization beam splitter using photonic crystal.Using the difference of the dispersive feature for TE and TM mode terahertz wave,the device can make TE and TM mode terahertz wave output from different ports,realizing the function of polarization bean split.The result shows that the extinction ratio for both TE and TM are larger than 15dB and 20.5dB respectively.The total size of the polarization beam splitter structure is only 7.9a×7.9a?1.02 mm×0.99mm?.The device designed has a novel structure,small size,low transmission loss and hight split efficiency.2.Multi-channel terahertz wave power splitter based on 2-D photonic crystal.The device is designed by the theory of multimode interference and Y-shape waveguide,it can realize six-equal output and four-equal output by changing the temperature of local part of photonic crystal.The transmission of each output is nearly 16.5%with the whole transmission is 97.8%while it is in the sate of six-equal output when in the room temperature.After heating local part of photonic crystal,the device is in the state of four-equal output while the transmission of each output is nearly 24.4%with the whole transmission is 98%.3.Terahertz wave S-R latch based on 2-D photonic crystal.Using the destructive interference of terahertz wave,we design a NOR gate,and then constructure the terahertz wave S-R latch.The simulation result shows that the device can realize the function of S-R latch.The device may have application prospect in terahertz wave system in the future.4.Multi-channel terahertz wave demultiplexer based on 2-D photonic crystal.Modifying the longth of interaction regions properly,the device can realize the separately output of four terahertz wave with different frequency,which are f₁=0.5677THz,f₂=0.5192THz,f₃=0.54THz and f₄=0.6THz with transmission are98%,92%,94%and 88.2%respectively.The device has a compact structure with the whole size is 27a×29a?5.4 mm×5.8mm?.