Development of ultrahigh repetition rate, ultraviolet light source for efficient high-resolution photoelectron spectroscopy

2016 Fiscal Year Final Research Report

• Project/Area Number: 26800166
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics I
• Research Institution: The University of Tokyo
• Principal Investigator: Omachi Junko 東京大学, 大学院理学系研究科(理学部), 特任助教 (70724053)
• Research Collaborator: YOSHIOKA Kosuke 東京大学, 大学院工学系研究科, 准教授 (70451804) ; GONOKAMI Makoto (KUWATA Makoto) 東京大学, 総長 (70161809) ; ISHIZAKA Kyoko 東京大学, 大学院工学系研究科, 准教授 (20376651) ; SHIMOJIMA Takahiro 理化学研究所, 強相関物理部門, 研究員 (70581578)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: ファブリーペロー共振器 / 高繰り返し化 / ピコ秒チタンサファイアモード同期レーザー / 光電子分光

Outline of Final Research Achievements

Our aim is to develop the ultraviolet light source for a highly-effective, high-resolution, angle-resolved photoelectron spectroscopy (ARPES) with a spherical electron analyzer. A high-spectral-resolution measurement in a short acquisition time without the space charge effect requires the ultraviolet pulses with low pulse energy and high repetition rate. We made an active-controlled short cavity after the fourth harmonic of the light from a 10 ps, 74 MHz, Ti: sapphire mode-locked laser. We achieved the 15 times multiplication of the repetition rate (1.1 GHz) and a decrease by 2 orders of magnitude in the pulse energy as well, resulting in a decrease by 2 orders of magnitude in the acquisition time on an ARPES measurement without degrading the resolution compared to that with the original 74 MHz pulses. Additionally, we developed an active-controlled system onto the laser to stabilize a longitudinal-mode fluctuation, which is required when we use a high-finesse cavity.

Free Research Field

光物性、光源開発