Efficient Photoemission from Robust Ferroelectric Ceramics

Experimental results on photoemission by ferroelectric ceramic disks, with a possible interpretation, are presented. Two types of lead zirconate titanate lanthanum doped, PLZT, ceramics have been used for tests. 25 ps light pulses of 532 and 355 nm were used for excitation. The intensity ranged within the interval 0.1-3 GW/cm. The upper limit of the intensity was established by the damage threshold tested by the onset of ion emission. At low value of the intensity the yield was comparable at the two wavelengths. At the highest intensity of green light the emitted charge was 1 nC per 10 mm, but it was limited by the space charge effect. In fact, the applied field was only 20 kV/cm, allowed both by the mechanical design of the apparatus and the poor vacuum, 10−4 mbar. No surface processing was required. The measurement of the electron pulse length under way.