Nano-Patterned Cathode Surfaces for High Efficiency Photoinjectors

Present day photoinjector cathodes have a poor lifetime or inadequate quantum efficiency for advanced applications. In addition, the efficiency is constrained by the frequency up- conversion in the drive laser from infrared to ultraviolet photons. Novel nanofabrication techniques allow for the sub-wavelength patterning of grooves and hole-array surfaces on the cathode. Exploiting the surface plasmon resonance, such surfaces can increase the absorption of infrared photons directly, and thus improve efficiency, and negate the inefficient up-conversion process to ultraviolet. Commercial applications and other benefits: The results of the efforts will find immediate utility in present advanced accelerator and light source facilitates that employ high brightness photoinjectors which have direct impact on industrial, medical, defense and basic research applications.