Devices|32 Article(s)
Research on the design of metalens with achromatic and amplitude modulation
Yuanyuan XU, Yan GENG, Yu LIANG, Furui TANG, Yujuan SUN, and Yawei and WANG
Metalenses are two-dimensional planar metamaterial lenses, which have the advantages of high efficiency and easy integration. However, most metalenses cannot modulate the light intensity, which limits their applications. To deal with it, taking advantage of flexible regulation of the beam amplitude and phase by the metalens, the geometric phase method is selected to design the dual-function metalens. It can effectively eliminate chromatic aberration in a visible light band from 535 nm to 600 nm and achieve amplitude modulation. After transmitting the metalens, the amplitudes of the beam respectively turn into 0.2 and 0.9. In this way, the amount of transmission of metalens in the preset band can be quantitatively controlled. According to the distribution characteristics of light diffraction intensity, the metalens designed can play a dual modulation role of achromatism and interference double-beam equilibrium in the paper, to meet the needs of miniaturization and integration of the optical system. The achromatic and amplitude-modulated metalens will have great application potential in optical holographic imaging and super-resolution focusing.
Optoelectronics Letters
  • Publication Date: Jan. 01, 2023
  • Vol. 19, Issue 2, 77 (2023)
Terahertz dual-beam leaky-wave antenna based on composite spoof surface plasmon waveguide
Yukun BAI, and Sen and LI
In this paper, we propose a single-port dual-beam leaky-wave antenna (LWA) in the terahertz (THz) band based on a composite spoof surface plasmon polariton (SSPP) waveguide. The antenna can generate three independent transmission channels by exciting two independent modes inherent to hole and groove structures, respectively. By periodic modulation of the hole and groove structures, we achieve dual-beam scanning through a broad radiation angle using only the -1st space harmonics of the two modes, hence avoiding the instability of the -2rd space harmonic. Within the operating frequency range of 0.62—0.85 THz, the gain ranges from 13.5 dBi to 17 dBi for the backward beam, and from 6 dBi to 11.8 dBi for the forward beam. The antenna can accomplish continuous backward beam through broadside to forward beam scanning with a total scanning range of 116° and an average efficiency of about 92%. The antenna exhibits a great potential in the design of multi-transceiver radar system in the THz band and multi-beam LWAs.
Optoelectronics Letters
  • Publication Date: Jan. 01, 2023
  • Vol. 19, Issue 2, 72 (2023)
Decoding algorithm with multiple features based on optical camera communication system
Junming ZHANG, Wenxiao SHI, Qiang WANG, Anqi LIU, and Wei and LIU
The performance of decoding algorithm is one of the important influential factors to determine the communication quality of optical camera communication (OCC) system. In this paper, we first propose a decoding algorithm with adaptive thresholding based on the captured pixel values under an ideal environment, and then we further propose a decoding algorithm with multiple features, which is more suitable under the existence of the interference of light sources. The algorithm firstly determines the light-emitting diode (LED) array profile information by removing the interfering light sources through geometric features, and then identifies the LED state by calculating two grayscale features, the average gray ratio (AGR) and the gradient radial inwardness (GRI) of the LEDs, and finally obtains the LED state matrix. The experimental results show that the bit error ratio (BER) of the decoding algorithm with multiple features decreases from 1×10-2 to 5×10-4 at 80 m.
Optoelectronics Letters
  • Publication Date: Jan. 01, 2023
  • Vol. 19, Issue 2, 65 (2023)
Numerical study on a frequency-tunable actively mode-locked fiber laser
Guidao LIN, Qi CHEN, Jianchao LIU, and Zhenhong and WANG
We have numerically presented an actively mode-locked fiber laser with tunable repetition rate based on phase modulator. By finely optimizing intra-cavity parameters, the ultrashort pulses with tunable repetitive frequency at giga hertz level can be easily generated due to the balance between dispersion and nonlinearity in the fiber laser cavity. When the pulse frequency is changed from 1.0 GHz to 4.2 GHz, the spectral width increases from ~15.65 nm to ~27.25 nm. In addition, the corresponding pulse duration decreases from ~81.59 ps to ~31.57 ps. Moreover, these output pulses with giga hertz repetitive rates and the picosecond widths can be further compressed by using the reasonable dispersion medium. For the pulse regime with repetition frequency at giga hertz level, the obtained smallest pulse duration is about ~62 fs based on chirp pulse compression. We hope that these simulation results can promote further research and application in the ultrashort pulse lasers with high repetition rate.
Optoelectronics Letters
  • Publication Date: Jan. 01, 2023
  • Vol. 19, Issue 1, 20 (2023)
High-performance ZnO humidity sensor synthesized by coprecipitation with PVP as surfactant for human respiration detection
Jianping MAN, Weiyuan GU, Ziyan HU, Xiaozong DOU, and Hongyan and ZHANG
A high-performance zinc oxide (ZnO)/polyvinylpyrrolidone (PVP) humidity sensor was prepared by simple coprecipitation method with PVP as surfactant. The coprecipitation method has low reaction temperature, little energy consumption and simple preparation, which is suitable for large-scale production. The PVP makes sample’s surface with more hydroxyl and oxygen vacancies than pure ZnO, which can absorb more water molecules and promote the decomposition of water molecules into H3O+ to form effective ion conduction. When the molar ratio of PVP to ZnO is 1: 1, the ZnO/PVP humidity sensor has low hysteresis (~4.2%), short response/recovery time (9/10 s), excellent stability and high sensitivity with more than 4 orders of magnitude in relative humidity (RH) range from 11% to 95%. Moreover, the ZnO/PVP humidity sensor can distinguish different respiratory states of human body, which has a potential in monitoring and prevention of respiratory diseases.
Optoelectronics Letters
  • Publication Date: Jan. 01, 2023
  • Vol. 19, Issue 1, 1 (2023)
Optimization for tandem organic light-emitting diodes based on Firpic
Pei WANG, Zhen WANG, and Xin ZHENG
Optoelectronics Letters
  • Publication Date: Jan. 01, 2018
  • Vol. 14, Issue 5, 350 (2018)
Thin-core fiber-optic biosensor for DNA hybridization detection
Shao-cong LONG, Yan-ru ZHU, Mu-yun HU, Yi-fan QI, Yun-rui JIANG, Bo LIU, and Xu ZHANG
A real-time label-free DNA biosensor based on thin-core fiber (TCF) interferometer is demonstrated experimentally. The proposed biosensor is constructed by splicing a TCF between two segments of single mode fibers (SMFs) and in-tegrated into a microfluidic channel. By modifying the TCF surface with monolayer poly-l-lysine (PLL) and sin-gle-stranded deoxyribonucleic acid (ssDNA) probes, the target DNA molecules can be captured in the microfluidic channel. The transmission spectra of the biosensor are measured and theoretically analyzed under different biosensing reaction processes. The results show that the wavelength has a blue-shift with the process of the DNA hybridization. Due to the advantages of low cost, simple operation as well as good detection effect on DNA molecules hybridization, the proposed biosensor has great application prospects in the fields of gene sequencing, medical diagnosis, cancer de-tection and environmental engineering.
Optoelectronics Letters
  • Publication Date: Jan. 01, 2018
  • Vol. 14, Issue 5, 346 (2018)
1 550 nm long-wavelength vertical-cavity surface emit-ting lasers
Li-jie LIU, Yuan-da WU, Yue WANG, Jun-ming AN, and Xiong-wei HU
Optoelectronics Letters
  • Publication Date: Jan. 01, 2018
  • Vol. 14, Issue 5, 342 (2018)
Research on mode division multiplexer with graded-index distribution, low loss and low crosstalk
Qian-qian LIU, Hong-jun ZHENG, Xin LI, Cheng-lin BAI, Wei-sheng HU, and Ru-yuan YU
A graded-index mode division multiplexer with low loss and low crosstalk is proposed. The transmission channel adopts a pure silica core with large effective area to achieve low attenuation, which effectively reduces the splicing loss with pure silica core few-mode transmission fiber. Low differential mode group delay is realized by using grad-ed-index distribution. Also the effective index difference of the modes is greater than 0.5×10-3 to ensure low crosstalk between modes. The performance of the mode division multiplexer is investigated using the beam propagation method and full-vector finite element method. The result shows that the coupling efficiency of multiplexer is better than .0.479 dB, and the extinction ratio is higher than 31.2 dB in the wavelength of 1 400—1 700 nm. In C band, the aver-age coupling efficiency of all mode channels of multiplexer is better than that of .0.140 dB, which shows flatness. The proposed scheme is an effective way to implement a multiplexer with low crosstalk, low loss, low fusion loss, high coupling efficiency, high extinction ratio and wide operating band.
Optoelectronics Letters
  • Publication Date: Jan. 01, 2018
  • Vol. 14, Issue 5, 336 (2018)
Numerical research on whispering-gallery modes in a triple-layer-coated microsphere resonator
Meng-yu WANG, Xue-ying JIN, and Ke-yi WANG
Optoelectronics Letters
  • Publication Date: Jan. 01, 2018
  • Vol. 14, Issue 5, 331 (2018)