Fig. 1. Thermonuclear system：（a） schematic diagrams of the ITER； （b） China EAST；（c） Max Planck Institute for Plasma Physics （IPP） ；（d） ITER； （e） the Germany Tokamak；（f） the United States DⅢ-D

Fig. 2. MW gyrotrons （From Japan，Russia，US and Europe）

Fig. 3. The CTS system：（a） the CTS system in-vessel front-end components；（b） the configuration of the CTS receiver beams；（c） the location and size of the CTS scattering volumes；（d） a photo of the 250 GHz gyrotron for CTS diagnostics by Institute of Applied Physics Russian Academy of Sciences and Gycom Ltd.；（e） the time trace of CTS raw data；（f） the spectrogram of one gyrotron pulse in the same discharge during the ICRH heating

Fig. 4. SEM photos of different samples after sintering，the grain growth of traditional sintered samples was observed only at 1 700 ℃ when samples were at （a） 1 600 ℃；（b） 1 650 ℃；（c） 1 700 ℃，and （d） 1 750 ℃，millimeter-wave sintering，the scanning electron microscope photos of samples at （e） 1 375 ℃； （f） 1 450 ℃；（g） 1 550 ℃；（h） 1 600 ℃，the grain growth has been observed at 1 375 ℃；（i） millimeter-wave sintering Y₂O₃ to 1 700 ℃ for 4 hours；（j） traditional sintering Y₂O₃ to 1 700 ℃ for 4 hours；（k） millimeter-wave sintering Gd₂O₃ to 1 700 ℃ for 4 hours；（l） traditional sintering Gd₂O₃ to 1 700 ℃ for 4 hours；（m） millimeter-wave sintering Yb₂O₃ to 1 700 ℃ for 4 hours；（n） traditional sintering Yb₂O₃ to 1 700 ℃ for 4 hours；（o） millimeter-wave sintered hydroxyapatite （HA） and （p） conventional sintered HA SEM；（q） densification curve of microwave sintering at different frequencies；（r） the curve of the central temperature and the difference between the central temperature and the surface temperature of the samples sintered by microwave at different frequencies

Fig. 5. The gyrotron system：（a） general view of the gyrotron system for ceramic sintering based on compact gyrotron assembly with 24-GHz/3-kW；（b） two-frequency gyro-device-based technological system；（c） general view of the technological system with the 300-GHz/3-kW gyrotron FU CW I

Fig. 6. Schematic diagrams and microphotographs：（a） schematic diagrams of the gyrotron-based system for diamond growth；（b） microphotographs and Raman shift of the surface of the as-grown diamond films deposited at 50% Ar concentration and at various CH₄ concentrations；（c） high purity Si produced by 24 GHz MMW-PECVD

Fig. 7. Diagram of the experimental setup for CO₂ decomposition by microwave plasma excited by gyrotron and the photo of plasma structure

Fig. 8. （a） Magic Angle Spinning （MAS） DNP-NMR system；（b） schematic of the gyrotron FDESR system and ESR spectra of sample powder with different duty ratios；（c） principle of gyrotron-based RAD spectroscopy；（d） hyperfine splitting（HFS） system；（e） X-ray Detected Magnetic Resonance （XDMR） system

Fig. 9. （a） The DNP-NMR of Burker；（b） the DNP-NMR of University of Warwick with EIK；（c） the DNP-NMR of MIT with 460 GHz gyrotron；（d） the NMR system with Bruker's DNP probe built by MIT；（e） 200 MHz DNP-NMR based on FU CW IV Gyrotron

Fig. 10. （a） Skin-depth （δ in mm） versus frequency （in GHz） of a wet tissue medium；（b） plot of frequency versus surface temperature-rise per second for a given EM power applied across 30 GHz through 300 GHz relative to conventional temperature-rise per second at microwaves （2.54 GHz） in the endometrial lining；（c） the experimental setup and instrumentation of tumor ablation，growth curves of the tumors （controlled and treated） after the irradiation at 107 GHz （left） and 203 GHz（right） followed by PDT

Fig. 11. （a） Millimeter wave antivirus system；（b） results of 95 GHz irradiating coronavirus；（c） the seedling growth of cabbage seeds treated with 24 GHz，600 W microwave for 1 second；（d） the comparison experiment by microwave to treat seeds under dry and water-soaking

Fig. 12. （a） Schematic view of ADS system；（b） schematic of ADS on a military vehicle；（c） active denial of weapons armored vehicles；（d） burning of skin tissue

Fig. 13. （a） Experimental setup of wireless power transfer with the 303 GHz gyrotron；（b） measurement setup of WPT with the 265 GHz gyrotron installed at 830 mm from the rectenna；（c） the WPT experimental setup with the W-band gyrotron

Fig. 14. （a） Millimeter wave drilling system；（b） internal configuration of the rock exposure test chamber and photos of the peaked ridged surface ablated away by the 28 GHz gyrotron beam；（c） scheme of the quasi-optical transmission line for melting rock

Fig. 15. （a） Thrust generation process；（b） the schematic image of Japanese H-IIB and the 109 g model rocket launched in a multi-pulse operation