Effect of concentration on the formation time of diffraction rings in spatial self-phase modulation
Yilin He, Jingdi Zhang, Si Xiao, Yingwei Wang, and Jun He
A new unsaturated wind-chime model is proposed for calculating the formation time of the diffraction rings induced by spatial self-phase modulation (SSPM) in molybdenum disulfide suspension. To optimize the traditional wind-chime model, the concentration variable of 2D materials was introduced. The results of the unsaturated wind-chime model match quite well with the SSPM experimental results of molybdenum disulfide. Based on this model, the shortest formation time of diffraction rings and their corresponding concentration and light intensity can be predicted using limited data. Theoretically, by increasing the viscosity coefficient of the solution, the response time of the diffraction ring, to reach the maximum value, can be significantly reduced. It has advanced significance in shortening the response time of photonic diodes.
  • Sep. 17, 2021
  • Chinese Optics Letters
  • Vol.20 Issue, 1 011901 (2022)
  • DOI:10.3788/COL202220.011901
Q-switched mode-locked multimode fiber laser based on a graphene-deposited multimode microfiber
Jia-Wen Wu, Yu-Xin Gao, Xu-Bin Lin, Jin-Gan Long, Hu Cui, Zhi-Chao Luo, Wen-Cheng Xu, and Ai-Ping Luo
We report Q-switched mode-locked (QML) pulses generation in an Yb-doped multimode fiber (MMF) laser by using a graphene-deposited multimode microfiber (GMM) for the first time, to the best of our knowledge. The single-wavelength QML operation with the central wavelength tunable from 1028.81 nm to 1039.20 nm and the dual-wavelength QML operation with the wavelength spacing tunable from 0.93 nm to 5.79 nm are achieved due to the multimode interference filtering effect induced by the few-mode fiber and MMF structure and the GMM in the cavity. Particularly, in the single-wavelength QML operation, the fifth harmonic is also realized owing to the high nonlinear effect of the GMM. The obtained results indicate that the QML pulses can be generated in the MMF laser, and such a flexible tunable laser has promising applications in optical sensing, measuring, and laser processing.
  • Sep. 17, 2021
  • Chinese Optics Letters
  • Vol.19 Issue, 12 121402 (2021)
  • DOI:10.3788/COL202119.121402
Multifrequency superscattering pattern shaping
Yao Qin, Jinying Xu, Yineng Liu, and Huanyang Chen
Multifrequency superscattering is a phenomenon in which the scattering cross section from a subwavelength object simultaneously exceeds the single-channel limit at multiple frequency regimes. Here, we achieve simultaneously, within a graphene-coated subwavelength structure, multifrequency superscattering and superscattering shaping with different engineered scattering patterns. It is shown that multimode degenerate resonances at multiple frequency regimes appearing in a graphene composite structure due to the peculiar dispersion can be employed to resonantly overlap electric and magnetic multipoles of various orders, and, as a result, effective multifrequency superscattering with different engineered angular patterns can be obtained. Moreover, the phenomena of multifrequency superscattering have a high tolerance to material losses and some structural variations. Our work should anticipate extensive applications ranging from emission enhancing, energy harvesting, and antenna design with improved sensitivity and accuracy due to multifrequency operation.
  • Sep. 02, 2021
  • Chinese Optics Letters
  • Vol.19 Issue, 12 123601 (2021)
  • DOI:10.3788/COL202119.123601
Strong coupling with absorption and emission features of Ag@Au hollow nanoshells interacting with J-aggregated dye molecules
Tianchen Zhao, Qiang Ma, Yajie Bian, Yuyi Zhang, Yiting Liu, Xiaolei Zhang, Botao Wu, E Wu, Shitao Lou, and Qingyuan Jin
We investigate the strong coupling from 5,5’,6,6’-tetrachloro-1,1’-diethyl-3,3’-di(4-sulfobutyl)-benzimidazolocarbocyanine (TDBC) molecules near pure nano-triangular Ag prisms or Ag@Au hollow nanoshells. When TDBC molecules are deposited on pure Ag nanoprisms or Ag@Au hollow nanoshells with the plasmonic resonance peak, matching very closely with the absorption band of TDBC J-aggregates, obvious Rabi splitting can be observed due to the strong coupling regime. Meanwhile, the photoluminescence intensity decreased with the increasing of the temperature, verifying the decreasing plasmon–exciton coupling interaction in the higher temperature. Our experimental results are coincident with the simulation results calculated by finite-difference time-domain method.
  • Sep. 09, 2021
  • Chinese Optics Letters
  • Vol.19 Issue, 12 123602 (2021)
  • DOI:10.3788/COL202119.123602
Non-mechanical beam scanner based on VCSEL integrated amplifier with resonant wavelength detuning design
Shanting Hu, Xiaodong Gu, Masanori Nakahama, and Fumio Koyama
We demonstrate the non-mechanical beam steering and amplifier operation of a vertical cavity surface emitting laser (VCSEL) integrated Bragg reflector waveguide amplifier with a cut-off wavelength detuning design, which enables unidirectional lateral coupling, continuous electrical beam steering, and diffraction-limited divergence angle. We present the modeling of the proposed structure for unidirectional coupling between a seed single-mode VCSEL and slow-light amplifier. We also present the detailed operating characteristics including the near-field and far-field patterns, light/current characteristics, and lasing spectrum. The experimental measurements exhibit a single-mode output of over 8 mW under CW operation, a continuous beam steering range of 16°, and beam divergence below 0.1° as an optical beam scanner. The integrated amplifier length is as small as 0.9 mm, and thus we could expect much higher powers and higher resolution points by increasing the amplifier lengths.
  • Sep. 17, 2021
  • Chinese Optics Letters
  • Vol.19 Issue, 12 121403 (2021)
  • DOI:10.3788/COL202119.121403