Spectroscopy
Identifying self-trapped excitons in 2D perovskites by Raman spectroscopy [Invited]
Junze Li, Junchao Hu, Jiaqi Ma, Xinglin Wen, and Dehui Li
Chinese Optics Letters
  • Jul. 23, 2021
  • Vol.19, Issue 10 (2021)
Optical Design and Fabrication
Multi-focused droplet lens array inspired by movable-type printing technology
Bo Dai, Zhengmeng Zhou, Yan Long, Mingliang Pan, Zeyuan Song, and Dawei Zhang
Chinese Optics Letters
  • Jul. 23, 2021
  • Vol.19, Issue 10 (2021)
Optoelectronics
Carrier transport and photoconductive gain mechanisms of AlGaN MSM photodetectors with high Al Content
Zhicheng Dai, Yushen Liu, Guofeng Yang, Feng Xie, Chun Zhu, Yan Gu, Naiyan Lu, Qigao Fan, Yu Ding, Yuhang Li, Yingzhou Yu, and Xiumei Zhang
Chinese Optics Letters
  • Jul. 23, 2021
  • Vol.19, Issue 8 (2021)
Integrated Optics
Passive devices at 2 µm wavelength on 200 mm CMOS-compatible silicon photonics platform [Invited]
Hui Ma, Haotian Yang, Bo Tang, Maoliang Wei, Junying Li, Jianghong Wu, Peng Zhang, Chunlei Sun, Lan Li, and Hongtao Lin
Chinese Optics Letters
  • Jul. 22, 2021
  • Vol.19, Issue 7 (2021)
Fiber Optics and Optical Communications
Recent advance in hollow-core fiber high-temperature and high-pressure sensing technology [Invited]
Zhe Zhang, Yingying Wang, Min Zhou, Jun He, Changrui Liao, and Yiping Wang
Chinese Optics Letters
  • Jul. 22, 2021
  • Vol.19, Issue 7 (2021)
Editors' Picks
With the tremendous growth of modern wireless communications, crowded spectrum and waste of spectrum resources which limit the application of various wireless technologies, become the important issues, especially in beyond fifth generation (B5G) and sixth generation (6G) communications. Therefore, it is increasingly urgent to enhance spectrum utilization efficiency and to increase the wireless network capacity. Compared with the traditional frequency division duplex (FDD) and time division duplex (TDD), the in-band full-duplex (IBFD) technology transmitting and receiving signals simultaneously on the same frequency can double the spectrum utilization efficiency and data transmission rate, and has a great potential application in the new generation of mobile communications and satellite communications. However, in the process of IBFD communication, the transmitting antenna and the receiving antenna are generally on the same platform, the high-power signal sent from the transmitting antenna will interfere the low-power signal of interest (SOI) that is received by the receiving antenna, or even submerge it completely, which is called radio frequency (RF) self-interference. This kind of interference is at the same frequency as the SOI, so it is impossible to filter it out by a notch filter or to select the SOI by a narrow band pass filter. Therefore, RF self-interference is a key issue to be resolved for the application of IBFD technology.
Chinese Optics Letters
  • Jul. 13, 2021
  • Vol.19, Issue 7 (2021)
Editors' Picks
The topological valley photonic crystal has recently attracted extensive attention owing to its superior properties like possibility to produce edge state below the light line and showing ultra-low loss when passing 120° sharp bends. Designing broadband and lossless valley photonic crystal waveguide is an important goal for researchers. Methods such as changing the shape of holes and inverse design have been used to achieve this goal. Now that broadband lossless valley waveguide is merely achieved based on Si valley photonic crystal with high refractive index. Thus achieving broadband valley photonic crystal waveguide based on materials with relatively low refractive is extremely necessary. For instance, valley photonic crystal based on BaTiO3 has already been used to construct adjustable optical switch and valley photonic crystal based on SiN has already used to construct waveguide coupler for single WSe2 monolayer.
Chinese Optics Letters
  • Jul. 01, 2021
  • Vol.19, Issue 6 (2021)
On the Cover
Nonlinear Talbot effect is a near-field nonlinear diffraction phenomenon in which the self-imaging of periodic object is formed by the second harmonic of the incident laser beam. Different from its conventional linear analogue, the periodic object here is made with spatially modulated second-order nonlinear coefficient of the medium, and the spatial resolution in Talbot self-imaging is improved by a factor of 2 thanks to frequency doubling. Consequently, the nonlinear Talbot effect is superior in applications that require high resolution imaging and processing, such as nonlinear optical microscopy, lithography, spectrometry, and material characterization.The nonlinear Talbot effect was first observed in periodically poled LiTaO3 crystals, which are also known as nonlinear photonic crystals. The self-imaging of 1D periodically and 2D hexagonally poled ferroelectric domain structures was observed by using the second harmonic generated in the crystals. Following this pioneering work, the dependence of nonlinear Talbot distance on parameters of nonlinear photonic crystals and the fractional nonlinear Talbot effects were also investigated. Despite of these recent achievements, the fundamental properties and capabilities of nonlinear Talbot effect have not been thoroughly studied so far. For instance, very useful characteristic of Talbot effect is its capability to produce defect-free images from imperfect structures, property known as self-healing. While such capability of image restoration has been well studied in linear Talbot effect, it has never been investigated in the regime of nonlinear optics.
Chinese Optics Letters
  • Jun. 23, 2021
  • Vol.19, Issue 6 (2021)
Editors' Picks
With the rapid development of broadband centers, cloud-based services, the Internet of Things, and 5G services, network traffic is growing at a vigorous rate, which requires optical communication networks with higher capacity and lower power consumption. As the building block of optical communication networks, the function of the optical modulator is to realize the high-speed conversion of information from the electrical domain to the optical domain, and to convert data transmission from cable to ultra-low loss fiber. Lithium niobate (LiNbO3, LN) has been the dominant material platform for optical modulators widely used in optical fiber communications due to its excellent physical properties, such as its high electro-optic (EO) Pockels coefficient, low optical absorption, high intrinsic modulation bandwidth, and long-term material reliability. However, commercial LN modulators rely on titanium-diffused or proton-exchange waveguides. Such weakly confined optical waveguides are not beneficial to achieving strong electro-optic interaction. In the issue, such modulators have low modulation efficiency (~10V·cm) and large device sizes.
Chinese Optics Letters
  • Jun. 17, 2021
  • Vol.19, Issue 6 (2021)