Precision measurement of quantum degenerate bulk excitons by excitonic Lyman spectroscopy

2016 Fiscal Year Final Research Report

• Project/Area Number: 25707024
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Partial Multi-year Fund
• Research Field: Condensed matter physics I
• Research Institution: The University of Tokyo
• Principal Investigator: Yoshioka Kosuke 東京大学, 工学(系)研究科(研究院), 准教授 (70451804)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 励起子 / ボース・アインシュタイン凝縮 / 吸収イメージング / 周波数コム

Outline of Final Research Achievements

We have succeeded to demonstrate the absorption imaging for trapped 1s paraexcitons in cuprous oxide at 7 K using the excitonic Lyman specrsocopy. This is the first observation of the absorption image in exciton systems in general. that probes 1s paraexcitons via the 1s-2p transition. We have developed a theory that describes the frequency shift of the excitonic internal transitions in a strain-induced trap, and we have compared the numerical results with our experiment. We also extended this experimental method in the mid-infrared to our dilution refrigerator, where we have successfully observed the absorption image of a quantum degenerate exciton gas at around 100 mK. In addition, we have developed two mode-locked femtosecond lasers and controlled them to be ultrafine optical frequency combs. This is the first step towards fine spectroscopy of solids using femtosecond frequency combs.

Free Research Field

量子エレクトロニクス