Fractional optical vortex laser and its frequency extension toward a terahertz region

2014 Fiscal Year Final Research Report

• Project/Area Number: 24360022
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Applied optics/Quantum optical engineering
• Research Institution: Chiba University
• Principal Investigator: OMATSU Takashige 千葉大学, 融合科学研究科(研究院), 教授 (30241938)
• Co-Investigator(Renkei-kenkyūsha): MIYAMOTO Katsuhiko 千葉大学, 大学院融合科学研究科, 准教授 (20375158)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: レーザー / 量子エレクトロニクス / 特異点光学 / 量子光学

Outline of Final Research Achievements

The first chirality control of an optical vortex output from a vortex-pumped optical parametric oscillator was demonstrated. It is found that the chirality of the optical vortex was fully identical to that of the 1um pump vortex beam. Over 2mJ, 2um optical vortex with a topological charge of ± 1 was generated. It is also found that a fractional vortex with a half integer topological charge can also be selectively generated owing to a coherent coupling between the first-order vortex and Gaussian modes. Furthermore, a widely tunable mid-infrared (6.3 - 12um) optical vortex laser was established by employing a ZGP difference frequency generator pumped by a 2um optical vortex laser with a cascaded KTP geometry. The mid-infrared vortex output carried the same topological charge as that of the 1um pump output without any destruction. A pulse energy of over 0.1mJ was
measured in the wavelength region of 6.5-12um.

Free Research Field

非線形光学