An XUV laser generated planar plasma microwave reflector

Summary form only given. Agile microwave reflectors are of interest as a potential replacement of phased arrays in radar applications. Microwave reflection from an XUV (/spl lambda/=193 nm) excimer laser (Wmax=20 mJ, r=17 ns) produced rectangular Tetrakis(dimethyl-amino)ethylene (TMAE) plasma column of dimensions 2.2 cm wide, 0.7 cm thick and up to 40 cm long has been demonstrated. This work demonstrates reflection of X-band microwaves at normal incidence by a planar TMAE plasma sheet of dimensions 7.8 cm wide, 0.7 cm thick and up to 40 cm long generated with the same excimer laser. Suprasil XUV lenses coated for 98% transparency at /spl lambda/=193 nm are used to generate the sheet beam profile. The plasma is in the far field of an X-band rectangular aperture antenna used to launch the microwaves. Amplitude and phase measurements of the reflected and transmitted microwave signal is achieved with microwave interferometers utilizing magic-tees. Three dimensional plasma density and temperature profiles as a function of time are obtained with Langmuir probes and compared with a measurement based on microwave transmission through the plasma. Langmuir triple probe measurements indicate that the peak plasma temperature is about 1 eV and densities are on the order of 10/sup 13/ cm/sup -3/.