Observation of two-photon photoemission from cesium telluride photocathodes excited by a near-infrared laser
We explore nonlinear photoemission in cesium telluride (Cs$$_2$$Te) photocathodes where an ultrashort ($$\sim 100$$ fs full width at half max) 800-nm infrared laser is used as the drive-laser in lieu of the typical $$\sim 266$$-nm ultraviolet laser. An important figure of merit for photocathodes, the quantum efficiency, we define here for nonlinear photoemission processes in order to compare with linear photoemission. The charge against drive-laser (infrared) energy is studied for different laser energy and intensity values and cross-compared with previously performed similar studies on copper [P. Musumeci et al., \emph{Phys. Rev. Lett.}, \textbf{104}, 084801 (2010)], a metallic photocathode. We particularly observe two-photon photoemission in Cs$$_2$$Te using the infrared laser in contrast to the anticipated three-photon process as observed for metallic photocathodes.
- Research Organization:
- Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- Grant/Contract Number:
- AC02-07CH11359; FG02-08ER41532
- OSTI ID:
- 1623375
- Alternate ID(s):
- OSTI ID: 1348275
- Report Number(s):
- FERMILAB-PUB-16-559-AD-APC; arXiv:1612.02956; oai:inspirehep.net:1502649; TRN: US2106867
- Journal Information:
- Applied Physics Letters, Vol. 110, Issue 9; ISSN 0003-6951
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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