Experimental detection and analysis of the Morse critical point of open electrodynamical structure involved in diffraction radiation oscillator

Until the present time the direct experimental detection of the Morse critical points (MCP) of dispersion equations of open electrodynamical structures has been lacking. In the millimeter wave region, this is because the proper theoretical analysis performed for oscillations of a simplest open structure like a confocal resonator calls for impractical geometrical dimensions. This disadvantage has been overcome through the use of a suitable electrodynamical structure like an open resonator involved in a diffraction radiation oscillator. The constructional feature providing the experiment feasibility is the reflecting diffraction grating which is embedded in one of the resonator mirrors and much changes the spectral characteristics of the canonical structure