Development of a Vacuum Ultra-Violet Laser-Based Angle-Resolved Photoemission System with a Super-High Energy Resolution Better Than 1 meV

摘要

The design and performance of the first vacuum ultra-violet (VUV) laser-basedangle-resolved photoemission (ARPES) system are described. The VUV laser with aphoton energy of 6.994 eV and bandwidth of 0.26 meV is achieved from the secondharmonic generation using a novel non-linear optical crystal KBe2BO3F2 (KBBF).The new VUV laser-based ARPES system exhibits superior performance, includingsuper-high energy resolution better than 1 meV, high momentum resolution,super-high photon flux and much enhanced bulk sensitivity, which aredemonstrated from measurements on a typical Bi2Sr2CaCu2O8 high temperaturesuperconductor. Issues and further development related to the VUV laser-basedphotoemission technique are discussed.