Millimeter-Wave Band Multi-Mirror Open Resonator. E- and H- Polarized Oscillations
This work provides the experimental research results of E- and H-polarized oscillations of the complex multi-mirror open resonator (OR) , one of the mirrors of which is represented by the echelette reflective grating. The essential difference between the spectra of E- and H- polarized oscillations of complex open resonator (COR) is noted. It is evident that within the range of measurements performed for the H-polarization, only one oscillation mode is excited while in the case with the E-polarization there are excited several of such modes. In this case the self-collimation reflection from the echelette grating determines the conditions for excitation of the OR, which condition is the dispersive element forming up the OR spectrum. Some functional capabilities implied by the design of the suggested multi-mirror open resonant system are also discussed. The suggested multi-mirror open resonant system can find wide application in millimeter-wave band electronics for frequency stabilization of the electron-vacuum and solid-state devices.
Research on orotron oscillator with dispersive open resonant system
Theoretical and experimental results of an investigation into a new resonant system have been obtained. This system is named the sphere-corner-echelette open resonator (SCEOR) due to the employment of a mirror that was formed by two echelettes at the angles of 45° to the resonator axis. It turns ont that this resonator is excited on the specific modes not unique to others oscillating systems.There are presented the results of the experimental research of the orotron oscillator with the SCEOR. The spectrum of this device contains only the fundamental modes such as theT E M006,T E M007,T E M008. The efficiency of the orotron is improved, when all other factors are the same the orotron with a much used sphere-cylindrical open resonator.
Improved orotron performance in the 50- to 75-GHz frequency region
New experimental results for the Harry Diamond Laboratories (HDL) orotron, a Smith-Purcell free-electron laser, have been obtained. Emphasis was placed on improving the 100-mW output power previously obtained with this device by using a new, more powerful ribbon-beam electron gun and a new open resonator. The orotron was tuned continuously from about 50 to 75 GHz on a TEM208Fabry-Perot mode; more than a watt of output power was measured on this mode. Considerably more power, approximately 5 W, was obtained at 65.65 GHz on a TEM209mode. Oscillation of the orotron was also observed on backward wave modes. In addition, it was found that improvements in beam quality lead to higher power orotron operation.