Broadband single-shot imaging spectroscopy using a micro-step echelon optics

2014 Fiscal Year Final Research Report

• Project/Area Number: 23241034
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Nanomaterials/Nanobioscience
• Research Institution: Yokohama National University
• Principal Investigator: TAKEDA Jun 横浜国立大学, 工学(系)研究科(研究院), 教授 (60202165)
• Co-Investigator(Kenkyū-buntansha): KITAJIMA Jmasahiro 防衛大学校, 応用科学群, 教授 (00343830) ; KIKUCHI Azusa 横浜国立大学, 工学研究院, 准教授 (30452048) ; KATAYAMA Ikufumi 横浜国立大学, 工学研究院, 准教授 (80432532)
• Project Period (FY): 2011-04-01 – 2015-03-31
• Keywords: シングルショット / フェムト秒 / 不可逆光誘起現象 / 紫外吸収剤 / 可視化

Outline of Final Research Achievements

We have developed broadband single-shot femtosecond spectroscopy in time-frequency space using a reflective echelon mirror. The echelon mirror is employed to make a spatially encoded time-delay for the white-light continuum probe pulse; it produces a temporal step of 66 fs and an overall time-delay of 33 ps. By utilizing this technique, we have observed not only an internal conversion dynamics in organic molecules but also an ultrafast crystalline-to-amorphous phase-change in chalcogenide alloys.
In case of chalcogenide alloys, the observed rise time to reach the amorphization was 130~200 fs, suggesting that the ultrafast amorphization can be attributed to the rearrangement of Ge atoms from an octahedral to a tetrahedral structure.
We also revealed the excited states and photo-sensitization effects in several UV absorbers, which are next targets to perform our single-shot spectroscopy.

Free Research Field

光物性