Contents
2020
Volume: 18 Issue 9
15 Article(s)

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Research Articles
Atomic and Molecular Optics
Fiber Optics and Optical Communications
Augmented communications: spectral efficiency and security enhanced visible light communications by design
Monette H. Khadr, and Hany Elgala
Chinese Optics Letters
  • Publication Date: Sep. 10, 2020
  • Vol. 18, Issue 9, 090601 (2020)
Digital-analog hybrid optical phase-lock loop for optical quadrature phase-shift keying
Shaowen Lu, Yu Zhou, Funan Zhu, Jianfeng Sun, Yan Yang, Ren Zhu, Shengnan Hu, Xiaoxi Zhang, Xiaolei Zhu, Xia Hou, and Weibiao Chen
Chinese Optics Letters
  • Publication Date: Sep. 10, 2020
  • Vol. 18, Issue 9, 090602 (2020)
General
Multi-technique analysis of an ancient stratified glass eye bead by OCT, μ-XRF, and μ-Raman spectroscopy
Junqing Dong, Qinghui Li, and Yongqing Hu
In this Letter, we report a combination of non-invasive analysis of the cross-section structure, phase, and chemical composition combining optical coherence tomography (OCT) with spectroscopic methods such as X-ray analytical microscope (μ-XRF) and micro-Raman spectroscopy (μ-RS), which allow us to effectively and conveniently identify the colorants used for each color region and the glass-making process of an ancient multicolored stratified glass eye bead. The results reveal that the sophisticated colors of the glass bead arise from the transition metals and chemical compound crystals deliberately added in the same base glass and carefully adjusted by the glass maker to obtain four colors. We also propose and discuss the provenance of the glass bead. It was probably introduced to China through the Northern Silk Road from Egypt or the Eastern Mediterranean areas about 1400 years ago. The combined multi-analytical technique is the promising approach for precious cultural heritage research.
Chinese Optics Letters
  • Publication Date: Sep. 10, 2020
  • Vol. 18, Issue 9, 090001 (2020)
Imaging Systems
Naked-eye ghost imaging via photoelectric feedback
Gao Wang, Huaibin Zheng, Zhiguo Tang, Yuchen He, Yu Zhou, Hui Chen, Jianbin Liu, Yuan Yuan, Fuli Li, and Zhuo Xu
Chinese Optics Letters
  • Publication Date: Sep. 10, 2020
  • Vol. 18, Issue 9, 091101 (2020)
Lasers and Laser Optics
Power and spectral analyses in diode-pumped c-cut Pbnm Tm:YAP laser
Jacek Kwiatkowski
Detailed power and spectral analysis of a diode-pumped c-cut Pbnm 3 at.% Tm-doped yttrium aluminum perovskite (Tm:YAP) laser in a continuous wave (CW) operation is presented. The laser was experimentally examined in terms of the dependence on the transmittance and radius of curvature of the output coupling mirrors. At room temperature, for an output coupling transmission of 10.8%, the maximum output power of 6.35 W was obtained under a total absorbed pump power of 13.67 W with an optical-to-optical conversion efficiency of 46.5%. The highest slope efficiency of 60.4% was indicated. A detailed spectral analysis was presented. For its dependence on output coupler transmission, the Tm:YAP laser generates wavelengths at approximately 1940 nm or 1990 nm.
Chinese Optics Letters
  • Publication Date: Sep. 10, 2020
  • Vol. 18, Issue 9, 091401 (2020)
Experimental investigation on residual reflectance of Nd:glass amplifier edge cladding
Junjiang Hu, Liyan Zhang, Jiachuan Ni, Tao Meng, Lei Wen, Youkuo Chen, Jingping Tang, Biao Wang, Shubin Chen, Wei Chen, and Lili Hu
Chinese Optics Letters
  • Publication Date: Sep. 10, 2020
  • Vol. 18, Issue 9, 091402 (2020)
Broadband photochromic effect and photoluminescence modulation in rare-earth-doped (Pb,La)(Zr,Ti)O3 ceramics
Long Xu, Ruiqi Zhu, and Caixia Xu
Chinese Optics Letters
  • Publication Date: Sep. 10, 2020
  • Vol. 18, Issue 9, 091403 (2020)
Laser transverse modes of spherical resonators: a review [Invited] | On the Cover
Y. F. Chen, C. C. Lee, C. H. Wang, and M. X. Hsieh
The study of structured laser beams has been one of the most active fields of research for decades, particularly in exploring laser beams with orbital angular momentum. The direct generation of structured beams from laser resonators is deeply associated with the formation of transverse modes. The wave representations of transverse modes of spherical cavities are usually categorized into Hermite–Gaussian (HG) and Laguerre–Gaussian (LG) modes for a long time. Enormous experimental results have revealed that the generalized representation for the transverse modes is the Hermite–LG (HLG) modes. We make a detailed overview for the theoretical description of the HLG modes from the representation of the spectral unitary group of order 2 in the Jordan–Schwinger map. Furthermore, we overview how to derive the integral formula for the elliptical modes based on the Gaussian wave-packet state and the inverse Fourier transform. The relationship between the HLG modes and elliptical modes is linked by the quantum Fourier transform. The most striking result is that the HLG modes can be exactly derived as the superposition of the elliptical modes without involving Hermite and Laguerre polynomials. Finally, we discuss the application of the HLG modes in characterizing the propagation evolution of the vortex structures of HG beams transformed by an astigmatic mode converter. This overview certainly provides not only a novel formula for transverse modes, but also a pedagogical insight into quantum physics.
Chinese Optics Letters
  • Publication Date: Sep. 10, 2020
  • Vol. 18, Issue 9, 091404 (2020)
Optoelectronics
Photonic-assisted single system for microwave frequency and phase noise measurement | Editors' Pick
Jingzhan Shi, Fangzheng Zhang, De Ben, and Shilong Pan
Chinese Optics Letters
  • Publication Date: Sep. 10, 2020
  • Vol. 18, Issue 9, 092501 (2020)
Other Areas of Optics
Optical edge detection with adjustable resolution based on liquid crystal polarization gratings
Yang Yang, Xinyang Liu, Yan Wu, Ting Li, Fan Fan, Huihui Huang, and Shuangchun Wen
Chinese Optics Letters
  • Publication Date: Sep. 10, 2020
  • Vol. 18, Issue 9, 093501 (2020)
Plasmonics and Metamaterials
Plasmonic Luneburg lens and plasmonic nano-coupler
Lei Zhang, Lin Wang, Yanqing Wu, and Renzhong Tai
Chinese Optics Letters
  • Publication Date: Sep. 10, 2020
  • Vol. 18, Issue 9, 092401 (2020)
Active formatting modulation of electromagnetically induced transparency in metamaterials | Editors' Pick
Hao Sun, Yuhua Tang, Yuze Hu, Jie You, Hengzhu Liu, and Xin Zheng
Chinese Optics Letters
  • Publication Date: Sep. 10, 2020
  • Vol. 18, Issue 9, 092402 (2020)
Tunable terahertz absorber based on transparent and flexible metamaterial
Junyu Xiao, Ruiwen Xiao, Rongxuan Zhang, Zhixiong Shen, Wei Hu, Lei Wang, and Yanqing Lu
We demonstrate a tunable terahertz (THz) absorber based on an indium tin oxide (ITO) metamaterial. The upper ITO cross-shaped metasurface with different arm lengths is fabricated by direct femtosecond laser etching. The thickness of the middle dielectric layer is only 60 μm, which makes the absorber very transparent and flexible. The experimental results show that the THz resonant peaks have a high performance near 1 THz. By setting spacers of different thicknesses between the middle layer and the ITO mirror, a new type of tunable THz absorber is proposed. Its absorption peak frequency can be continuously adjusted from 0.92 to 1.04 THz between TE and TM polarization. This transparent THz metamaterial absorber is expected to be widely used in THz imaging, sensing, and biological detection.
Chinese Optics Letters
  • Publication Date: Sep. 10, 2020
  • Vol. 18, Issue 9, 092403 (2020)
Ultrafast Optics
Regular uniform large-area subwavelength nanogratings fabricated by the interference of two femtosecond laser beams via cylindrical lens
Kaiqiang Cao, Long Chen, Ke Cheng, Zhenrong Sun, and Tianqing Jia
Inhomogeneity and low efficiency are two important factors that hinder the wide application of laser-induced periodic surface structures. Two-beam interference is commonly used to fabricate gratings with interference periods. This study reports regular and uniform periodic ripples fabricated efficiently by the interference of two femtosecond laser beams via a cylindrical lens. The interference period is adjusted to be an integer multiple of the wavelength of a surface plasmon polariton. Regular and uniform subwavelength nanogratings (RUSNGs) on a silicon wafer of a diameter of 100 mm are fabricated with a scanning velocity of 6–9 mm/s. Bright and pure colors (including purple, blue, and red) are demonstrated on different patterns covered with RUSNGs.
Chinese Optics Letters
  • Publication Date: Sep. 10, 2020
  • Vol. 18, Issue 9, 093201 (2020)

About the Cover

The SU(2) transformation in the Jordan-Schwinger map is exploited to derive the wave function for the Hermite-Laguerre-Gaussian (HLG) modes which are the generalized transverse modes of spherical laser resonators. The image is numerical patterns for the high-order HLG mode.