title: Direct generation of 2-ps blue pulses from gain-switched InGaN VCSEL assessed by up-conversion technique.
abstract: Ultra-short pulses in blue region generated from compact and low-cost semiconductor lasers have attracted much attention for a wide variety of applications. Nitride-based vertical-cavity surface-emitting lasers (VCSELs), having intrinsic high material gain and short cavities, favor the generation of ultra-short blue pulses via a simple gain-switching technique. In this study, we fabricated a single-mode InGaN VCSEL consisting of 10-period InGaN/GaN quantum wells (QWs). The output pulses were evaluated accurately with an up-conversion measurement system having time resolution of 0.12 ps. We demonstrated that ultra-short blue pulses, as short as 2.2 ps at 3.4 K and 4.0 ps at room temperature, were generated from the gain-switched InGaN VCSEL via impulsive optical pumping, without any post-processing. The gain-switched pulses we obtained should greatly promote the development of ultra-short blue pulse generation. In addition, this successful assessment demonstrates the up-conversion technique's usefulness for characterizing ultra-short blue pulses from semiconductor lasers.
authors.affiliation: 1] Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan [2].
authors.forename: Akifumi
authors.initials: A
authors.lastname: Asahara
authors.affiliation: 1] Department of Electronic Engineering, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China [2] Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan [3].
authors.forename: Shaoqiang
authors.initials: S
authors.lastname: Chen
authors.affiliation: 1] Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan [2].
authors.forename: Takashi
authors.initials: T
authors.lastname: Ito
authors.affiliation: Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yoshita
authors.affiliation: Department of Physics &Department of Electronic Engineering, Xiamen University, Xiamen 361005, Fujian, China.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Physics &Department of Electronic Engineering, Xiamen University, Xiamen 361005, Fujian, China.
authors.forename: Baoping
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Suemoto
authors.affiliation: Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan.
authors.forename: Hidefumi
authors.initials: H
authors.lastname: Akiyama