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Effect of anions from calcium sources on the synthesis of nano-sized xonotlite fibers
Fei LIU, Sha CHEN, Qian LIN, Xiao-dan WANG, and Jian-xin CAO
The xonotlite fibers were synthesized via the hydrothermal synthesis method with CaO and SiO2as the raw materials and the molar ratio of Si/Ca of 1.0. Effect of anions from various calcium sources on the microstructure of the xonotlite fibers is studied in this paper. These obtained products were characterized by X-rayThe xonotlite fibers were synthesized via the hydrothermal synthesis method with CaO and SiO2as the raw materials and the molar ratio of Si/Ca of 1.0. Effect of anions from various calcium sources on the microstructure of the xonotlite fibers is studied in this paper. These obtained products were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM) techniques to investigate their crystalline phase, crystal structure and morphology. The results indicate that anion from various calcium sources has little influence on the crystalline phases of xonotlite fibers but poses a great impact on their morphologies. Xonotlite fibers with single crystal characteristics and large aspect ratio of 50—100 were successfully fabricated from CaCl2as calcium material at 225 °C for 15 h. The existence of Cl-anion in the CaO-SiO2-H2O system significantly contributes to the formation of xonotlite crystal..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 81 (2017)
Effects of unit size on current density and illuminance of micro-LED-array
Chao TIAN, Shu-xu GUO, Jing-qiu LIANG, Zhong-zhu LIANG, and Feng-li GAO
A 300 μm×300 μm light emitting diode (LED) chip is divided into nine 80 μm×80 μm units with 30 μm spacing between adjacent ones. After arraying, the total saturation light output power and the maximum injection current are enhanced by 5.19 times and nearly 7 times, respectively. In addition, the test results A 300 μm×300 μm light emitting diode (LED) chip is divided into nine 80 μm×80 μm units with 30 μm spacing between adjacent ones. After arraying, the total saturation light output power and the maximum injection current are enhanced by 5.19 times and nearly 7 times, respectively. In addition, the test results demonstrate that the illuminance uniformity on the receiving surface reaches the optimum when the spacing between the arrays is equal to the maximum flat condition. The larger the number of arrays, the greater the area with uniform illuminance on the receiving surface..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 84 (2017)
Magnetic fluid based deformable mirror for aberration correction of liquid telescope
Jun-qiu WU, Zhi-zheng WU, Xiang-hui KONG, Zhu ZHANG, and Mei LIU
A magnetic fluid based deformable mirror (MFDM) that could produce a large stroke more than 100 μm is designed and demonstrated experimentally with respect to the characteristics of the aberration of the liquid telescope. Its aberration correction performance is verified by the co-simulation using COMSOL and MATLAB. FuA magnetic fluid based deformable mirror (MFDM) that could produce a large stroke more than 100 μm is designed and demonstrated experimentally with respect to the characteristics of the aberration of the liquid telescope. Its aberration correction performance is verified by the co-simulation using COMSOL and MATLAB. Furthermore, the stroke performance of the MFDM and the decentralized linear quadratic Gaussian (LQG) mirror surface control approach are experimentally evaluated with a prototype of MFDM in an adaptive optics system to show its potential application for the large aberration correction of liquid telescopes..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 90 (2017)
Electromagnetically induced transparency in terahertz metamaterial based on two-bright-mode resonator
Yan LIU, Sai CHEN, Fei FAN, Meng CHEN... and Sheng-jiang CHANG|Show fewer author(s)
An electromagnetically induced transparency (EIT) in metamaterial resonator with two bright modes and one dark mode at the terahertz (THz) band is numerically and experimentally demonstrated. Different from two kinds of the traditional passive modulations, our design can realize the passive modulation of EIT phenomenonAn electromagnetically induced transparency (EIT) in metamaterial resonator with two bright modes and one dark mode at the terahertz (THz) band is numerically and experimentally demonstrated. Different from two kinds of the traditional passive modulations, our design can realize the passive modulation of EIT phenomenon by adding another bright mode resonator. Simulated and experimental results show that the transmission peak varies for incident THz waves with different polarization directions due to its asymmetric structure, which provides a novel way to realize high efficiency switch and modulation..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 95 (2017)
Development of a portable mid-infrared methane detection device
Hui-fang LIU, Qi-xin HE, Chuan-tao ZHENG, and Yi-ding WANG
Based on direct absorption spectroscopy (DAS), a portable methane (CH4) detection device was implemented. The device mainly includes a dual-channel non-dispersive infrared sensor (integrated with an infrared light source, light path and pyroelectric detector), a driving circuit of the sensor, an ARM11 embedded WinCE syBased on direct absorption spectroscopy (DAS), a portable methane (CH4) detection device was implemented. The device mainly includes a dual-channel non-dispersive infrared sensor (integrated with an infrared light source, light path and pyroelectric detector), a driving circuit of the sensor, an ARM11 embedded WinCE system, and a LabVIEW-based data-processing platform. Experiments were carried out with prepared CH4samples to investigate the sensing performance. The relative detection error is less than 9.14% within the measuring range of 0—7×10-2. For a CH4sample with concentration of 0 (i.e., pure nitrogen), the measured concentration fluctuation range is -1.2×10-5—+2×10-5. An Allan deviation analysis on the gas sample with concentration of 0 indicates that the 1σ limit of detection (LoD) of the device is 4.8×10-6 with an average time of 1 s. Experiments were performed on three CH4samples with different concentrations to test the response time, which is validated to be less than 20 s. Due to the small size of the ARM11 embedded system and the powerful data processing capability of the LabVIEW platform, the proposed portable and miniaturized CH4sensor shows a good application prospect in mining operations and some other industrial fields..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 100 (2017)
A simplified tunable frequency interval optical frequency comb generator using a single continuous-wave laser
Li LIU, Tie-feng XU, Zhen-xiang DAI, Shi-xun DAI, and Tai-jun LIU
We propose and demonstrate a simplified and tunable frequency interval optical frequency comb (OFC) generator based on a dual-drive Mach-Zehnder modulator (DD-MZM) using a single continuous-wave (CW) laser and low-power radio frequency (RF) driven signal. A mathematical model for the scheme is established. The 21- and We propose and demonstrate a simplified and tunable frequency interval optical frequency comb (OFC) generator based on a dual-drive Mach-Zehnder modulator (DD-MZM) using a single continuous-wave (CW) laser and low-power radio frequency (RF) driven signal. A mathematical model for the scheme is established. The 21- and 29-mode OFCs with frequency interval ranging from 6 GHz to 40 GHz are obtained under DD-MZM driven by a low-power RF signal within a maximum bandwidth of 1.12 THz. The generated OFCs exhibit spectral flatnesses of less than 0.5 dB and 0.8 dB within bandwidths of 160 GHz and 400 GHz, respectively..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 104 (2017)
Transient emission wavelength estimation for DFB laser with temperature tuning
Jin-yi LI, Chen-zhi QIAO, Li-mei SONG, and Qing-hua GUO
The prediction method of dynamic wavelength is proposed for temperature tuning process. The temperature of the thermistor integrated in laser diode (LD) module is recorded to predict the LD chip temperature. Then according to the injection current and priori tuning characteristics of the LDs, the emission wavelength isThe prediction method of dynamic wavelength is proposed for temperature tuning process. The temperature of the thermistor integrated in laser diode (LD) module is recorded to predict the LD chip temperature. Then according to the injection current and priori tuning characteristics of the LDs, the emission wavelength is estimated in real time. The method is validated by using a 1.58 μm distributed feedback (DFB) LD. The absorption spectra of mixture gas of CO2and CO are measured by means of the thermal tuning gas sensing system. The center wavelength of each absorption line is compared with the data in HITRAN2012 database. The results show that the deviations are less than 5 pm. This method fully meets the needs of spectroscopic measurement, and can be applied to spectroscopy, optical communications and other fields..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 108 (2017)
An on-chip electroosmotic micropump with a light- addressable potentiometric sensor
Xue-liang LI, Shi-bin LIU, Ping-ping FAN, Werner Carl Frederik... and Yoshinobu Tatsuo|Show fewer author(s)
An on-chip electroosmotic (EO) micropump (EOP) was integrated in a microfluidic channel combined with a light-addressable potentiometric sensor (LAPS). The movement of EO flow towards right and left directions can be clearly observed in the microfluidic channel. The characteristics of photocurrent-time and photocurrentAn on-chip electroosmotic (EO) micropump (EOP) was integrated in a microfluidic channel combined with a light-addressable potentiometric sensor (LAPS). The movement of EO flow towards right and left directions can be clearly observed in the microfluidic channel. The characteristics of photocurrent-time and photocurrent-bias voltage are obtained when buffer solution passes through the sensing region. The results demonstrate that the combination of an on-chip EOP with an LAPS is feasible..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 113 (2017)
Green phosphorescent organic light-emitting devices based on different electron transport layers combining with fluorescent sub-monolayer
Hui-shan YANG, Hui-yu GUO, and Li-shuang WU
We report a small molecule host of 4,4(-N,N)-dicarbazole-biphenyl (CBP) doped with 8% tris(2-phenylpyridine) iridium (Irppy3) for use in efficient green phosphorescent organic light-emitting devices (PHOLEDs) combined with different electron transport layers of Alq and BAlq. The PHOLEDs exhibit maximum current efficienWe report a small molecule host of 4,4(-N,N)-dicarbazole-biphenyl (CBP) doped with 8% tris(2-phenylpyridine) iridium (Irppy3) for use in efficient green phosphorescent organic light-emitting devices (PHOLEDs) combined with different electron transport layers of Alq and BAlq. The PHOLEDs exhibit maximum current efficiency and power efficiency of 19.8 cd/A and 6.21 lm/W, respectively. The high performance of such PHOLEDs is attributed to the better electron mobile ability of BAlq and sub-monolayer quinacridone (QAD) as carrier trapping layer and equal charge carrier mobilities of hole and electron to form the broad carrier recombination zone in the emitting layer, which can reduce the triplet-triplet annihilation and improve the efficiency of the device..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 116 (2017)
A compact tunable metamaterial filter based on split-ring resonators
Ya-juan ZHAO, Bi-cheng ZHOU, Ze-kui ZHANG, Rong ZHANG, and Bao-yi LI
A tunable metamaterial filter is designed based on split-ring resonators (SRRs) in this paper. The metamaterial filter has a compact size of 15 mm×20 mm, and miniaturization is realized by using the SRRs. By loading tunable devices, the continuous operation of the filter is realized at X band (from 10.7 GHz to 12 A tunable metamaterial filter is designed based on split-ring resonators (SRRs) in this paper. The metamaterial filter has a compact size of 15 mm×20 mm, and miniaturization is realized by using the SRRs. By loading tunable devices, the continuous operation of the filter is realized at X band (from 10.7 GHz to 12 GHz), the bandwidth is about 13%, the minimum return loss is 35 dB, and the maximum insertion loss is 0.37 dB. The results illustrate that the metamaterial filter shows the compact size, wide bandwidth and good band pass characteristics..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 120 (2017)
Compensation to the output drift for cooled infrared imaging systems at various ambient temperatures
Qi-jie TIAN, Song-tao CHANG, Feng-yun HE, and Yan-feng QIAO
A method is proposed to compensate the output drift for cooled infrared imaging systems at various ambient temperatures. By calibrating the cryogenic infrared detector which absorbs the radiant flux of blackbody directly, the internal factors can be obtained. Then, by combining the calibration result of infrared imaginA method is proposed to compensate the output drift for cooled infrared imaging systems at various ambient temperatures. By calibrating the cryogenic infrared detector which absorbs the radiant flux of blackbody directly, the internal factors can be obtained. Then, by combining the calibration result of infrared imaging system at an arbitrary ambient temperature, the output drift can be calculated and compensated at various integration time and ambient temperatures. Experimental results indicate that the proposed method can eliminate the effect of ambient temperature fluctuation on the system output efficiently..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 123 (2017)
Highly efficient terahertz generation from periodically-poled RbTiOPO4
Zhong-yang LI, Meng-tao WANG, Si-lei WANG, De-gang XU, and Jian-quan YAO
Terahertz (THz) generation by periodically-poled RbTiOPO4(PPRTP) with a quasi-phase-matching scheme based on cascaded difference frequency generation (DFG) processes is theoretically analyzed. The cascaded Stokes and anti-Stokes interaction processes are investigated from coupled wave equations. The THz intensities andTerahertz (THz) generation by periodically-poled RbTiOPO4(PPRTP) with a quasi-phase-matching scheme based on cascaded difference frequency generation (DFG) processes is theoretically analyzed. The cascaded Stokes and anti-Stokes interaction processes are investigated from coupled wave equations. The THz intensities and quantum conversion efficiency are calculated. Compared with that of non-cascaded DFG processes, the THz intensity in 7-order cascaded DFG processes is increased to 2.95 times. The quantum conversion efficiency of 149.9% in cascaded processes can be realized, which exceeds the Manley-Rowe limit..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 127 (2017)
Luminescence properties of tunable red-green emitting phosphor Ba2Ca(BO3)2:Eu3+, Tb3+
Ming-yi MA, Wu-rui SONG, Chun-yan JI, Mei-fan LI... and Hai-yan LIU|Show fewer author(s)
A series of Eu3+or Tb3+doped Ba2Ca(BO3)2phosphors were synthesized by a high temperature solid state method, and the luminescence properties are investigated. Ba2Ca(BO3)2:Tb3+can show an obvious green emission, and the peak locates at 551 nm, which corresponds to the 5D4→7F5transition of Tb3+. Ba2Ca(BO3)2:Eu3+can preseA series of Eu3+or Tb3+doped Ba2Ca(BO3)2phosphors were synthesized by a high temperature solid state method, and the luminescence properties are investigated. Ba2Ca(BO3)2:Tb3+can show an obvious green emission, and the peak locates at 551 nm, which corresponds to the 5D4→7F5transition of Tb3+. Ba2Ca(BO3)2:Eu3+can present the characteristic emission of Eu3+, and the peak locates at 600 nm, which is ascribed to the 5D0→7F2 transition of Eu3+. In order to achieve the emission-tunable phosphors, the Eu3+/Tb3+co-doped Ba2Ca(BO3)2are synthesized. When tuning the Eu3+or Tb3+concentration, Ba2Ca(BO3)2:Eu3+, Tb3+can both show the tunable emission, which may be induced by the energy transfer from Tb3+to Eu3+..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 131 (2017)
A tension insensitive PbS fiber temperature sensor based on Sagnac interferometer
Xing-hu FU, Jiang-peng ZHANG, Kai-li YANG, Yan-hua DONG... and Wei-hong BI|Show fewer author(s)
In this paper, a tension insensitive PbS fiber temperature sensor based on Sagnac interferometer is proposed and demonstrated. The sensing mechanism of tension and temperature is analyzed. The relationships between the interference spectrum, temperature and tension are analyzed, respectively. The experimental temperatuIn this paper, a tension insensitive PbS fiber temperature sensor based on Sagnac interferometer is proposed and demonstrated. The sensing mechanism of tension and temperature is analyzed. The relationships between the interference spectrum, temperature and tension are analyzed, respectively. The experimental temperature range is 36—70 °C. The experimental results show that the interference spectrum is red shifted, and its sensitivity is 53.89 pm/°C. In tension experiment, the tension range is 0—1 400 με. The experimental results show that there is no wavelength shift in the interference spectrum. The sensor is immune to tension cross-sensitivity compared with other sensors. It can be used for temperature testing in aerospace, chemistry and pharmacy..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 135 (2017)
A novel improved SLM scheme of the PAPR reduction technology in CO-OFDM systems
Jian-guo YUAN, Qian SHEN, Jing-xin WANG, Yong WANG... and Yu PANG|Show fewer author(s)
The higher peak-to-average power ratio (PAPR) is a major shortcoming of coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. Selective mapping (SLM) technology can effectively reduce the probability of high PAPR, but it has higher computational complexity, and requires additional bandwidth to The higher peak-to-average power ratio (PAPR) is a major shortcoming of coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. Selective mapping (SLM) technology can effectively reduce the probability of high PAPR, but it has higher computational complexity, and requires additional bandwidth to transmit the side information, which will affect the transmission efficiency of the system. In response to these shortcomings, a novel improved SLM (NI-SLM) scheme with low complexity and without side information is proposed. Simulation results show that the proposed scheme can exponentially reduce the computational complexity, and the bit error rate (BER) performance can greatly approach the original signal. What’s more, it shows the better PAPR reduction performance..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 138 (2017)
Non-invasive human extremely weak pulse wave measurement based on a high-precision laser self-mixing interferometer
Ying-bin WEI, Zheng WEI, Wen-cai HUANG, Jie ZHANG, and Li-juan ZHANG
In this paper, a technique based on laser self-mixing effect for acquiring pulse wave profile is proposed and demonstrated. For the characteristics of extremely weak vibration in human pulse waves, a method of multiple reflections with external cavity is designed to improve the measurement accuracy to λ/4. Based on theIn this paper, a technique based on laser self-mixing effect for acquiring pulse wave profile is proposed and demonstrated. For the characteristics of extremely weak vibration in human pulse waves, a method of multiple reflections with external cavity is designed to improve the measurement accuracy to λ/4. Based on the fringe counting algorithm, one period of pulse wave is successfully reconstructed. The measurement results show that the root mean square error (RMSE) of the reconstructed pulse wave is 0.912 μm at sampling rate of 8 kHz. Besides, the correlation coefficients and heart beats of this method and the traditional photoplethysmography (PPG) measurement are analyzed..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 143 (2017)
Influence of linear birefringence on Faraday effect measurement for optical fibers
Huang-chao CHEN, Jian-xiang WEN, Yi HUANG, Wei-long DONG... and Ting-yun WANG|Show fewer author(s)
The influence of the linear birefringence on magneto-optical property measurement for optical fibers is investigated theoretically and experimentally. The evolution of polarization in fibers is simulated by the Jones matrix. To verify this theoretical model, a magneto-optical system is built to measure the input azimutThe influence of the linear birefringence on magneto-optical property measurement for optical fibers is investigated theoretically and experimentally. The evolution of polarization in fibers is simulated by the Jones matrix. To verify this theoretical model, a magneto-optical system is built to measure the input azimuth, output azimuth and ellipticity. The Faraday rotation of spun fibers with different pitches is measured. The Verdet constant increases, while the linear birefringence decreases as the pitch becomes smaller. For spun fibers with 1 mm pitch, the Verdet constant can be enhanced by about 20.7% at 660 nm, compared with that of the unspun fiber. The results indicate that smaller linear birefringence can provide more accurate Faraday rotation measurement..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 147 (2017)
Ship detection in optical remote sensing image based on visual saliency and AdaBoost classifier
Hui-li WANG, Ming ZHU, Chun-bo LIN, and Dian-bing CHEN
In this paper, firstly, target candidate regions are extracted by combining maximum symmetric surround saliency detection algorithm with a cellular automata dynamic evolution model. Secondly, an eigenvector independent of the ship target size is constructed by combining the shape feature with ship histogram of orientedIn this paper, firstly, target candidate regions are extracted by combining maximum symmetric surround saliency detection algorithm with a cellular automata dynamic evolution model. Secondly, an eigenvector independent of the ship target size is constructed by combining the shape feature with ship histogram of oriented gradient (S-HOG) feature, and the target can be recognized by AdaBoost classifier. As demonstrated in our experiments, the proposed method with the detection accuracy of over 96% outperforms the state-of-the-art method.1 efficiency switch and modulation..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 151 (2017)
Efficiency enhancement for the orbital angular momentum photon quantum interface via single photon frequency upconversion
Wen-jie WU, Jian-hui MA, Hai-feng PAN, E WU... and Wan-guo LIANG|Show fewer author(s)
As the application of orbital angular momentum (OAM) of photon quantum in quantum communication, the OAM photon quantum interface for the transmission wavelength from the telecom communication quantum information storage in visible regime is required. Here we demonstrate the efficiency enhancement for the OAM photon quAs the application of orbital angular momentum (OAM) of photon quantum in quantum communication, the OAM photon quantum interface for the transmission wavelength from the telecom communication quantum information storage in visible regime is required. Here we demonstrate the efficiency enhancement for the OAM photon quantum interface based on the frequency upconversion from telecom wavelength to visible regime by sum-frequency generation. The infrared photons at 1 558 nm carrying different OAM values could be converted to the visible regime at 622.2 nm with the optimal efficiency via adjusting the pump beam waist radius and intensity..
Optoelectronics Letters
- Publication Date: Sep. 13, 2018
- Vol. 13, Issue 2, 156 (2017)