Probing fluorescence quantum efficiency of single molecules in an organic matrix by monitoring lifetime change during sublimation
Penglong Ren, Shangming Wei, Pu Zhang, and Xue-Wen Chen
Quantum efficiency is a critical piece of information of a quantum emitter and regulates the emitter’s fluorescence decay dynamics in an optical environment through the Purcell effect. Here, we present a simple way to experimentally probe fluorescence quantum efficiency of single dibenzoterrylene molecules embedded in a thin anthracene microcrystal obtained through a co-sublimation process. In particular, we correlate the fluorescence lifetime change of single dibenzoterrylene molecules with the variation of the matrix thickness due to natural sublimation. With the identification of the molecule emission dipole orientation, we could deduce the near-unity intrinsic quantum efficiency of dibenzoterrylene molecules in the anthracene matrix.
  • May. 06, 2022
  • Chinese Optics Letters
  • Vol.20 Issue, 7 073602 (2022)
  • DOI:10.3788/COL202220.073602
LiNbO3 channel and ridge waveguides based on helium ion implantation combined with lithography and precise diamond dicing
Sumei Wang, Jinhua Zhao, Jinjun Gu, Mingyang Bu, Li Fan, Shuang Li, Xifeng Qin, Yicun Yao, Yingying Ren, and Lei Wang
  • May. 07, 2022
  • Chinese Optics Letters
  • Vol.20 Issue, 7 071301 (2022)
  • DOI:10.3788/COL202220.071301
Low-threshold continuous operation of fiber gas Raman laser based on large-core anti-resonant hollow-core fiber
Xinyue Zhu, Fei Yu, Dakun Wu, Yan Feng, Shufen Chen, Yi Jiang, and Lili Hu
Continuous operation of fiber gas Raman lasing at the 1135 nm wavelength is experimentally demonstrated with an output power exceeding 26 W. Rotational stimulated Raman scattering (Rot-SRS) is generated in the hydrogen gas filled 50 m homemade anti-resonant hollow-core fiber (AR-HCF). A single-frequency fiber laser at the 1064 nm wavelength is used as the pump source, and a minimum threshold of 31.5 W is measured where the core diameter of AR-HCF reaches 37 µm. Up to 40.4% power conversion efficiency of forward Rot-SRS is achieved in the single-pass configuration, corresponding to a quantum efficiency of 43.1%. Over 1 W strong backward Rot-SRS is observed in the experiment, ultimately limiting the further increase of Rot-SRS generation in the forward direction.
  • May. 07, 2022
  • Chinese Optics Letters
  • Vol.20 Issue, 7 071401 (2022)
  • DOI:10.3788/COL202220.071401
Inverse design of 1D color splitter for high-efficiency color imaging
Jiahao Li, Mengwei Cao, Weili Liang, Yilin Zhang, Zhenwei Xie, and Xiaocong Yuan
  • May. 06, 2022
  • Chinese Optics Letters
  • Vol.20 Issue, 7 073601 (2022)
  • DOI:10.3788/COL202220.073601
Underwater Bessel-like beams with enlarged depth of focus based on fiber microaxicon
Xiaoying He, Mengyuan Li, and Lan Rao
Underwater optical wireless communication, which is useful for oceanography, environmental monitoring, and underwater surveillance, suffers the limit of the absorption attenuation and Mie–Rayleigh scattering of the lights. Here, Bessel-like beams generated by a fiber microaxicon is utilized for underwater wireless propagation. Underwater, the cone angle for generating Bessel-like beams starts from 46°, which is smaller than that in air for Bessel-like beams. When the cone angle of the fiber microaxicons is about 140°, the depth of focus underwater, which is four times as long as the depth of focus in air, has enlarged about 28 µm, 36.12 µm, and 50.7 µm for 470 nm, 520 nm, and 632 nm visible lights. The transmission distance of the Bessel beams for visible lights has been simulated by using Henyey–Greenstein–Rayleigh phase function methods and spectral absorption by bio-optical model due to Monte Carlo methods. The results show that the propagation distance could reach 4000 m, which overcome the limit of the Mie–Rayleigh scattering and absorption attenuation underwater.
  • May. 07, 2022
  • Chinese Optics Letters
  • Vol.20 Issue, 7 072601 (2022)
  • DOI:10.3788/COL202220.072601
In-situ laser-induced surface damage inspection based on image super-resolution and adaptive segmentation method
Fengdong Chen, Jingyang Sun, Qian Wang, Hongbo Zhu, Fa Zeng, Yueyue Han, Cheng Lu, and Guodong Liu
In-situ laser-induced surface damage inspection plays a key role in protecting the large aperture optics in an inertial confinement fusion (ICF) high-power laser facility. In order to improve the initial damage detection capabilities, an in-situ inspection method based on image super-resolution and adaptive segmentation method is presented. Through transfer learning and integration of various attention mechanisms, the super-resolution reconstruction of darkfield images with less texture information is effectively realized, and, on the basis of image super-resolution, an adaptive image segmentation method is designed, which effectively adapts to the damage detection problems under conditions of uneven illumination and weak signal. An online experiment was carried out by using edge illumination and the telescope optical imaging system, and the validity of the method was proved by the experimental results.
  • Apr. 29, 2022
  • Chinese Optics Letters
  • Vol.20 Issue, 7 071101 (2022)
  • DOI:10.3788/COL202220.071101
Optical analysis method for fast plasma characterization of high-speed miniaturized synthetic jet
Ye Yuan, Yan Zhang, Cheng Guo, Xiaolu Kang, Zhong Yan, Xiaoping Huang, and Qing Zhao
In this paper, a new optical analysis method for plasma characterization is proposed. Plasma characteristics are obtained directly by measuring the plasma luminous color, rather than the complex spectral diagnosis method, which is difficult to obtain at high speed. By using the light transmittance curve of the human cornea, the RGB coordinates are calculated from the measured plasma spectrum data. Plasma characteristics are diagnosed using the Boltzmann plot method and the Stark broadening method. The corresponding relationship of the electron temperature, electron density data points, and luminous color is established and analyzed. Our research results indicate that this optical analysis method is feasible and promising for fast plasma characterization.
  • May. 06, 2022
  • Chinese Optics Letters
  • Vol.20 Issue, 7 073001 (2022)
  • DOI:10.3788/COL202220.073001