Journals >Chinese Optics Letters
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2014
Volume: 12 Issue 9
24 Article(s)
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Diffraction and Gratings
Shaping of focal field with controllable amplitude, phase, and polarization
Jingjing Hao, Zhongliang Yu, Zhaozhong Chen, Hao Chen, and Jianping Ding
We propose a method for configuring the distribution of amplitude, phase, and polarization in the focal region of vector beams. The polarization and phase of incident beam is spatially tailored so that it can produce a focal field that has elaborately prescribed shapes. Our work focuses on the design of a special focusWe propose a method for configuring the distribution of amplitude, phase, and polarization in the focal region of vector beams. The polarization and phase of incident beam is spatially tailored so that it can produce a focal field that has elaborately prescribed shapes. Our work focuses on the design of a special focus structure with two oval rings, wherein a phase gradient and polarization gradient exist in the inner and outer rings, respectively. The incident light yielding the desired focal field is determined based on an iterative scheme involving vectorial diffraction calculations and fast Fourier transforms. Simulations and experiments demonstrate the generation of a focal field with phase and polarization gradients, which may find applications in optical manipulation..
Chinese Optics Letters
- Publication Date: Aug. 23, 2014
- Vol. 12, Issue 9, 090501 (2014)
Fiber Optics and Optical Communications
Liquid refractive index sensor based on polymer fiber with micro-holes created by femtosecond laser
Wenchao Dong, Jue Wei, Xuehai Wang, Zhihui Kang, and Xiaofeng Xu
We present a liquid refractive index (RI) sensor based on step-index multimode polymer optical fiber with a micro-hole drilled by the femtosecond laser. The experimental results show that in the RI operation range of 1.333–1.473, the sensor has a good linear loss (dB) response to the liquid RI in the micro-holes and a We present a liquid refractive index (RI) sensor based on step-index multimode polymer optical fiber with a micro-hole drilled by the femtosecond laser. The experimental results show that in the RI operation range of 1.333–1.473, the sensor has a good linear loss (dB) response to the liquid RI in the micro-holes and a high sensitivity of 18 dB/RIU approximately. The experimental results are explained with the mode of the refraction loss caused by the hole–core interface and connection loss caused by the gap of the holes. The sensor has many advantages including high sensitivity and low cost..
Chinese Optics Letters
- Publication Date: Aug. 08, 2014
- Vol. 12, Issue 9, 090601 (2014)
Sample indexed spatial orthogonal frequency division multiplexing
Pankil Butala, Hany Elgala, and Thomas D.
Optical spatial modulation (OSM) is a multiple-transmitter technique that can provide higher data rates with low system complexity as compared with single-input single-output systems. Orthogonal frequency division multiplexing (OFDM) is widely implemented to achieve better spectral efficiency in wireless channels. AsymOptical spatial modulation (OSM) is a multiple-transmitter technique that can provide higher data rates with low system complexity as compared with single-input single-output systems. Orthogonal frequency division multiplexing (OFDM) is widely implemented to achieve better spectral efficiency in wireless channels. Asymmetrically clipped optical OFDM (O-OFDM) and DC-biased O-OFDM are two well-known O-OFDM techniques suitable for intensity-modulation direct-detection optical systems. In this work, sample indexed spatial OFDM (SIS-OFDM) is proposed to combine OSM and O-OFDM in a novel way and achieve significant performance gain. By assigning time-domain samples of the O-OFDM transmit symbol to different transmitters, SIS-OFDM achieves much better spectral efficiency and reduces computational complexity at the transmitter as compared with previous work that combines OSM with O-OFDM in the frequency domain. We also consider the impact of optical source biasing on overall performance, and the relative performance of imaging receiver (ImR) versus non-imaging receiver (NImR) design for our proposed SIS-OFDM technique. Results indicate that for an Ntx × Nrx multiple-input multiple-output configuration where Ntx = Nrx = 4, SIS-OFDM using ImR can achieve up to 135 dB of signal-to-noise ratio gain over comparable system using a NImR. Also, using Nsc number of O-OFDM subcarriers provides up to Nsc × log2(Ntx) additional bits per symbol of spectral efficiency over techniques that combine OSM and O-OFDM in the frequency domain..
Chinese Optics Letters
- Publication Date: Aug. 08, 2014
- Vol. 12, Issue 9, 090602 (2014)
RZ-OOK to NRZ-OOK format conversion based on a single fiber Bragg grating
Hui Cao, Xuewen Shu, Javid Atai, Qian Dong, Jun Zuo, GuoJie Chen, and Yu Yu
We propose a return-to-zero on-off keying (RZ-OOK) to non-return-to-zero (NRZ) OOK conversion scheme based on a single custom-designed fiber Bragg grating (FBG). The custom-made FBG is designed and syn-thesized using discrete layer-peeling algorithm. It is shown that such a FBG can replace the combination of interferomWe propose a return-to-zero on-off keying (RZ-OOK) to non-return-to-zero (NRZ) OOK conversion scheme based on a single custom-designed fiber Bragg grating (FBG). The custom-made FBG is designed and syn-thesized using discrete layer-peeling algorithm. It is shown that such a FBG can replace the combination of interferometer and the cascaded filter that are invariably employed together in the reported schemes for -RZ-OOK to NRZ-OOK format conversion. Simulation results show that the input 20-Gb/s RZ-OOK signals with different duty cycles can be converted into NRZ-OOK signals with high Q-factor..
Chinese Optics Letters
- Publication Date: Aug. 26, 2014
- Vol. 12, Issue 9, 090603 (2014)
Multi-hole plastic optical fiber force sensor based on femtosecond laser micromachining
Guoyu Tang, Jue Wei, Wei Zhou, Ruiqin Fan, Mingyu Wu, and Xiaofeng Xu
We study the theoretical and experimental effects of hole quantity and inter–inter-hole spacing on insertion loss for using femtosecond laser to make bend-sensitive multi-hole plastic optical fiber (POF), and also analyze the mechanism of bending loss in multi-hole POF. A force sensor based on bending loss of the multiWe study the theoretical and experimental effects of hole quantity and inter–inter-hole spacing on insertion loss for using femtosecond laser to make bend-sensitive multi-hole plastic optical fiber (POF), and also analyze the mechanism of bending loss in multi-hole POF. A force sensor based on bending loss of the multi-hole POF is fabricated. The measurement ranges from 0 to 65 N, and the maximum output change exceeds 15.51 dB with good linearity and repeatability, and the sensitivity is 0.24 dB/N..
Chinese Optics Letters
- Publication Date: Aug. 27, 2014
- Vol. 12, Issue 9, 090604 (2014)
Supercontinuum generation in a standard single-mode fiber by a Q-switched Tm, Ho:YVO4 laser
Jiancun Ren, Renlai Zhou, Shuli Lou, Wenbo Hou, Youlun Ju, and Yuezhu Wang
Broadband mid-infrared (IR) supercontinuum laser is generated in standard single-mode fiber-28 directly pumped by a 2054 nm nanosecond Q-switched Tm,Ho:YVO4 laser. The average output powers of 0.53 W in the ~1.95–2.5 μm spectral band and 0.65 W in the ~1.97–2.45 μm spectral band are achieved at pulse rate frequencies oBroadband mid-infrared (IR) supercontinuum laser is generated in standard single-mode fiber-28 directly pumped by a 2054 nm nanosecond Q-switched Tm,Ho:YVO4 laser. The average output powers of 0.53 W in the ~1.95–2.5 μm spectral band and 0.65 W in the ~1.97–2.45 μm spectral band are achieved at pulse rate frequencies of 7 and 10 kHz, and the corresponding optic-to-optic conversion efficiencies are 34.6% and 42.4% by considering the coupling efficiency. The output spectra have extremely high flatness in the range 2060–2400 and 2060–2360 nm with negligible intensity variation (<2%), respectively. The output pulse shape is not split, and pulse width is reduced from 29 to ~15.4 ns. The beam quality factor M2 is 1.06, measured using traveling knife-edge method, and the laser beam spot is also monitored by an IR vidicon camera..
Chinese Optics Letters
- Publication Date: Aug. 11, 2014
- Vol. 12, Issue 9, 090605 (2014)
Optical microfiber phase modulator directly driven with low-power light
Zhangqi Song, Yang Yu, Xueliang Zhang, Zhengtong Wei, and Zhou Meng
An optical microfiber phase modulator (OMPM) directly driven with low-power light is presented. Phase modulation response of OMPM is theoretically analyzed. A 10-mm optical microfiber (OM), tapered from conventional single-mode fiber, is inserted in one arm of a Michelson fiber interferometer. To drive the OMPM, 980-nmAn optical microfiber phase modulator (OMPM) directly driven with low-power light is presented. Phase modulation response of OMPM is theoretically analyzed. A 10-mm optical microfiber (OM), tapered from conventional single-mode fiber, is inserted in one arm of a Michelson fiber interferometer. To drive the OMPM, 980-nm wavelength light with sinusoidal intensity modulation is injected into the interferometer. The OMPM response properties are measured and p-phase modulation amplitude can be obtained with only 7.5-mW average power light at 1-kHz modulation frequency. The OMPMs shown in this study have advantages of simple structure, potential compact size, and low-power-driven light..
Chinese Optics Letters
- Publication Date: Aug. 26, 2014
- Vol. 12, Issue 9, 090606 (2014)
Imaging Systems
Three-dimensional imaging interferometric synthetic aperture ladar
Zhilong Zhao, Jin Wu, Yuanyuan Su, Na Liang, and Hongcheng Duan
A monostatic strip-map mode interferometric synthetic aperture ladar (SAL) is reported. Using a chirped laser of about 5 mW at 1550 nm wavelength as the illumination source and two cross-track receiving apertures with a baseline of 1.6 mm, the ladar can generate both well-focused two-dimensional SAL images without adopA monostatic strip-map mode interferometric synthetic aperture ladar (SAL) is reported. Using a chirped laser of about 5 mW at 1550 nm wavelength as the illumination source and two cross-track receiving apertures with a baseline of 1.6 mm, the ladar can generate both well-focused two-dimensional SAL images without adopting phase error removing techniques and three-dimensional images by interferometric SAL techniques. Detailed results are illustrated for retro-reflective or diffusive targets at a distance of 2.4 m..
Chinese Optics Letters
- Publication Date: Aug. 22, 2014
- Vol. 12, Issue 9, 091101 (2014)
Lasers and Laser Optics
Narrowband optical parametric amplifier for efficient conversion of high-energy pulse with high beam quality
Huanhuan Li, Xiaolei Zhu, Xiuhuan Ma, Shiguang Li, Chongde Huang, Junxuan Zhang, and Weibiao Chen
In a two-stage optical parametric amplifier based on KTiOAO4 crystals, we apply beam-overlapping technique to nanosecond signal pulse amplification, which results in high conversion efficiency and good beam quality. A signal pulse energy of 66 mJ at 1.572 μm wavelength is generated with 220 mJ of pump pulse input. A maIn a two-stage optical parametric amplifier based on KTiOAO4 crystals, we apply beam-overlapping technique to nanosecond signal pulse amplification, which results in high conversion efficiency and good beam quality. A signal pulse energy of 66 mJ at 1.572 μm wavelength is generated with 220 mJ of pump pulse input. A maxi-mum gain of 66 and a maximum pump depletion of as high as 44% are determined. The spectral linewidth of the amplified signal pulse is around 50 MHz, and the beam quality factor of M.2 is less than 2.3..
Chinese Optics Letters
- Publication Date: Aug. 25, 2015
- Vol. 12, Issue 9, 091401 (2014)
Fabrication of widely tunable ridge waveguide DBR lasers for WDM-PON
Liangshun Han, Song Liang, Can Zhang, Liqiang Yu, Lingjuan Zhao, Hongliang Zhu, Baojun Wang, Chen Ji, and Wei Wang
We report the fabrication of widely tunable ridge waveguide distributed Bragg reflector (DBR) lasers with InGaAsP butt-joint as grating material. The shape of the butt–joint interface is found to have significant effect on the properties of the lasers. It is shown that irregular mode jumps during wavelength tuning can We report the fabrication of widely tunable ridge waveguide distributed Bragg reflector (DBR) lasers with InGaAsP butt-joint as grating material. The shape of the butt–joint interface is found to have significant effect on the properties of the lasers. It is shown that irregular mode jumps during wavelength tuning can be avoided by a V-shaped butt–joint interface. From the fabricated device, 23 channels with 0.8 nm spacing and greater than 35 dB side mode suppression ratios are obtained. The different tuning characteristics of the ridge waveguide and the previously reported buried ridge stripe DBR lasers are discussed. Combined with the wide tuning range and the simple structure, the ridge waveguide DBR lasers are promising for use in wavelength division multiplexing passive optical networks (WDM-PONs)..
Chinese Optics Letters
- Publication Date: Aug. 26, 2014
- Vol. 12, Issue 9, 091402 (2014)
High-power diode-pumped ytterbium-doped fiber laser at 1150 nm
Yu Miao, Hanwei Zhang, Hu Xiao, and Pu Zhou
A model of steady-state rate equations including amplified spontaneous emission for long-wavelength ytterbi-um-doped fiber laser is set up, which provides design principle for a practical laser system. We demonstrate a diode-pumped all-fiber Yb-doped fiber laser at 1150 nm with an output power of 33.6 W, the optical efA model of steady-state rate equations including amplified spontaneous emission for long-wavelength ytterbi-um-doped fiber laser is set up, which provides design principle for a practical laser system. We demonstrate a diode-pumped all-fiber Yb-doped fiber laser at 1150 nm with an output power of 33.6 W, the optical efficiency is 60%..
Chinese Optics Letters
- Publication Date: Aug. 27, 2014
- Vol. 12, Issue 9, 091403 (2014)
Q-switched Er-doped fiber laser with low pumping threshold using graphene saturable absorber
R. Z., F. Ahmad, N. M., S. W., and H. Arof
We propose a Q-switched Er-doped fiber laser (EDFL) with a threshold pumping power as low as 7.4 mW, and demonstrate using graphene polyvinyl alcohol (PVA) thin film as a passive saturable absorber (SA). The SA is fabricated from graphene flakes, which is synthesized by electrochemical exfoliation of graphite at room tWe propose a Q-switched Er-doped fiber laser (EDFL) with a threshold pumping power as low as 7.4 mW, and demonstrate using graphene polyvinyl alcohol (PVA) thin film as a passive saturable absorber (SA). The SA is fabricated from graphene flakes, which is synthesized by electrochemical exfoliation of graphite at room temperature in 1% sodium dodecyl sulfate aqueous solution. The flakes are mixed with PVA solution to produce a thin film, which is then sandwiched between two ferrules to form a SA and integrated in the EDFL ring cavity to generate a stable Q-switched pulse train. The pulse train operates at 1560 nm with a threshold pump power of 7.4 mW. At maximum 1480 nm pump power of 33.0 mW, the EDFL generates an optical pulse train with a repetition rate of 27.0 kHz and pulse width of 3.56 μs. The maximum pulse energy of 39.4 nJ is obtained at a pump power of 14.9 mW. This laser can be used as a simple and low-cost light source for metrology, environmental sensing, and biomedical diagnostics..
Chinese Optics Letters
- Publication Date: Aug. 23, 2014
- Vol. 12, Issue 9, 091404 (2014)
Materials
Continuous zircon-type tetragonal YxBi0.95-xVO4:0.05Dy3+ solid solution: synthesis, characterization, and optical properties
Juan Yi, Yu'an Wang, Dacheng Zhou, and Jianbei Qiu
We synthesize continuous solid solutions with monophasic zircon-type structure of vanadates of formula YxBi0.95-xVO4:0.05Dy3+ (x = 0–0.95) using a combined method of co-precipitation and hydrothermal synthesis. The X-ray diffractometer patterns confirm the formation of a solid solution of YxBi0.95-xVO4:0.05Dy3+, and thWe synthesize continuous solid solutions with monophasic zircon-type structure of vanadates of formula YxBi0.95-xVO4:0.05Dy3+ (x = 0–0.95) using a combined method of co-precipitation and hydrothermal synthesis. The X-ray diffractometer patterns confirm the formation of a solid solution of YxBi0.95-xVO4:0.05Dy3+, and the results show that all the samples have monophasic zircon-type structure. The absorption spectra of the prepared phosphors show a blue-shift of the fundamental absorption band edge with increasing Y3+ content. An intense tunable characteristic emission of Dy3+ is observed with the increasing ratio of Y/Bi. Finally, the mechanism of luminescence of Dy3+ in the YxBi0.95-xVO4:0.05Dy3+ (x = 0–0.95) solid solution is analyzed and discussed..
Chinese Optics Letters
- Publication Date: Aug. 22, 2014
- Vol. 12, Issue 9, 091601 (2014)
Spectrum redshift effect of anatase TiO2 codoped with nitrogen and first transition elements
Yonghong Gu, Congzhong Cai, Qing Feng, and Yanhua Li
The electronic and optical properties, including band structure, density of states (DOS), absorption rate, refractive index, and dielectric function, of anatase TiO2 codoped with N and first transition elements are investigated using the plane wave pseudopotential method based on the density functional theory. The calcThe electronic and optical properties, including band structure, density of states (DOS), absorption rate, refractive index, and dielectric function, of anatase TiO2 codoped with N and first transition elements are investigated using the plane wave pseudopotential method based on the density functional theory. The calculation results show that TiO2 codoping with N and first transition elements (Sc, V, Cr, Mn, and Fe) lead to significant reduction of conduction band relative to the Fermi level, reduction of band gap width, formation of new donor, and acceptor impurity levels below the conduction band and above the valence band, and cause some redshifts of optical absorption band edge with the amount of redshift decrease in the following order: N–Fe > N–Cr > N–Mn. Further, the synergistic effect of shallow donor and acceptor levels enhances light excitation for effective separation of electron–hole pairs and enhancement of light absorption ability, thereby increasing the TiO2 photocatalytic properties. This study reveals that the visible-light absorption ability of the codoped anatase TiO2 decreases in the order of N–Fe > N–Cr > N–Mn > N–Sc > N–V > N, and does not monotonically follow the dopant atomic number. Especially, in N–Cr codoped TiO2, the 4s atomic orbit of Cr is not completely filled, which hybridized with the p electronic orbit most probably acts as photo-generated electron trap centers resulting in higher photocatalytic activity than that of N–Mn codoped TiO2..
Chinese Optics Letters
- Publication Date: Aug. 28, 2014
- Vol. 12, Issue 9, 091602 (2014)
Optical Devices
GaN-based p–i–n ultraviolet photodetectors with a thin p-type GaN layer on patterned sapphire substrates
Hongjuan Huang, Dawei Yan, Guosheng Wang, Feng Xie, Guofeng Yang, Shaoqing Xiao, and Xiaofeng Gu
We study the performance of GaN-based p–i–n ultraviolet (UV) photodetectors (PDs) with a 60 nm thin p-type contact layer grown on patterned sapphire substrate (PSS). The PDs on PSS exhibit a low dark current of ~2 pA under a bias of -5 V, a large UV/visible rejection ratio of ~7×103, and a high-quantum efficiency We study the performance of GaN-based p–i–n ultraviolet (UV) photodetectors (PDs) with a 60 nm thin p-type contact layer grown on patterned sapphire substrate (PSS). The PDs on PSS exhibit a low dark current of ~2 pA under a bias of -5 V, a large UV/visible rejection ratio of ~7×103, and a high-quantum efficiency of ~40% at 365 nm under zero bias. The average quantum efficiency of the PDs still remains above 20% in the deep-UV region from 280 to 360 nm. In addition, the noise characteristics of the PDs are also discussed, and the corresponding specific detectivities limited by the thermal noise and the low-frequency 1/f noise are calculated..
Chinese Optics Letters
- Publication Date: Aug. 11, 2014
- Vol. 12, Issue 9, 092301 (2014)
Design and fabrication of optical power splitters with large port count
Liangliang Wang, Junming An, Jiashun Zhang, Yuanda Wu, Jianguang Li, Hongjie Wang, Yue Wang, Pan Pan, Fei Zhong, Qiang Zha, Xiaojie Yin, Xiongwei Hu, and Degang Zhao
We design and fabricate compact, low loss, and high port-count optical power splitters of 1 × 128 and2 × 128 using silica-based planar lightwave circuit (PLC) technology on 6 inch quartz substrate. PLC tech-nology is mainly based on plasma enhanced chemical vapor deposition, photolithography, and etching. TheWe design and fabricate compact, low loss, and high port-count optical power splitters of 1 × 128 and2 × 128 using silica-based planar lightwave circuit (PLC) technology on 6 inch quartz substrate. PLC tech-nology is mainly based on plasma enhanced chemical vapor deposition, photolithography, and etching. The measured results show that the insertion loss, uniformity, and wavelength-dependent loss of 1 × 128 and 2 × 128 optical power splitters are less than 23, 1.43, and 0.92 dB and 23.3, 1.8, and 1.3 dB, respectively, in the wavelength range from 1.26 to 1.65 mm. The polarization-dependent losses are less than 0.16 and 0.2 dB, respectively, in the wavelengths of 1.31, 1.49, and 1.55 mm..
Chinese Optics Letters
- Publication Date: Aug. 22, 2014
- Vol. 12, Issue 9, 092302 (2014)
Thin Films
Highly surface-textured and conducting ZnO:Al films fabricated from oxygen-deficient target for Cu(In, Ga)Se2 solar cell application
Zhou Wang, Dongyun Wan, Fuqiang Huang, and Fangfang Xu
Highly conducting ZnO:Al (AZO) films are normally prepared through substrate heating and post-annealing in reducing atmosphere, which is deleterious to maintain the high transparency of films and the overall so-lar cell performance. Here we fabricate AZO films through one-step sputtering at room temperature using oxygeHighly conducting ZnO:Al (AZO) films are normally prepared through substrate heating and post-annealing in reducing atmosphere, which is deleterious to maintain the high transparency of films and the overall so-lar cell performance. Here we fabricate AZO films through one-step sputtering at room temperature using oxygen-deficient targets prepared via double crucible method. The best-performed AZO film achieves a low resistivity of 4.4 × 10-4 . cm, a high haze factor of 35.0%, and optimizes the efficiency of Cu (In, Ga)Se2 solar cell with a high value of 14.15%. This letter demonstrates that oxygen deficiency can induce high surface texture, conductivity, and boost solar cell performance..
Chinese Optics Letters
- Publication Date: Aug. 23, 2014
- Vol. 12, Issue 9, 093101 (2014)
Quantum Optics
Cavity linewidth narrowing by means of electromagnetically induced transparency in Rb with a longitudinal magnetic field
Haonan Chen, Kang Ying, Yafan Duan, Yueping Niu, and Shangqing Gong
We demonstrate a method for further reducing the cavity linewidth by the application of a small longitudinal magnetic field on the Rb cell. Because of the magnetic field multiple electromagnetically induced transparencies (EITs) are observed. The center EIT linewidth is measured as a function of the magnetic field. By We demonstrate a method for further reducing the cavity linewidth by the application of a small longitudinal magnetic field on the Rb cell. Because of the magnetic field multiple electromagnetically induced transparencies (EITs) are observed. The center EIT linewidth is measured as a function of the magnetic field. By utilizing the center EIT we narrow the cavity linewidth to 2 MHz which is half of the cavity linewidth without magnetic field..
Chinese Optics Letters
- Publication Date: Aug. 27, 2014
- Vol. 12, Issue 9, 092701 (2014)
Optics at Surfaces
Highly enhanced broadband infrared absorption of germanium by multi-layer plasmonic nano-antenna
Xiaolan Zhong, Ju Liu, and Zhiyuan Li
High-sensitivity and broad bandwidth photo-detector devices are important for both fundamental studies and high-technology applications. Here, by using three-dimensional (3D) finite-difference time-domain simulation, we design an optimized 3D multilayer gold nano-antenna to enhance the nearinfrared (NIR) absorption of High-sensitivity and broad bandwidth photo-detector devices are important for both fundamental studies and high-technology applications. Here, by using three-dimensional (3D) finite-difference time-domain simulation, we design an optimized 3D multilayer gold nano-antenna to enhance the nearinfrared (NIR) absorption of germanium nanoparticles. The key ingredient is the simultaneous presence of multiple plasmonic resonance modes with strong light-harvesting effect that encompass a broad bandwidth of germanium absorption band. The simulation results show more than two orders of magnitude enhanced absorption efficiency of germanium around 1550 nm. The design opens up a promising way to build high-sensitivity and broad bandwidth NIR photo-detectors..
Chinese Optics Letters
- Publication Date: Aug. 22, 2014
- Vol. 12, Issue 9, 092401 (2014)
Graded-index ridge surface plasmon polaritons waveguide
Chunwei Ye, Yumin Liu, Jie Wang, Hongbo Lv, and Zhongyuan Yu
We propose and analyze a long-range dielectric-loaded surface plasmon polariton (SPP) waveguide based on graded-index ridge over server millimeter distances. Then the influence of the dielectric thickness and the ridge refractive index on propagation length and mode width is discussed and simulated with the finite ele-We propose and analyze a long-range dielectric-loaded surface plasmon polariton (SPP) waveguide based on graded-index ridge over server millimeter distances. Then the influence of the dielectric thickness and the ridge refractive index on propagation length and mode width is discussed and simulated with the finite ele-ment method. The result shows that the SPP can propagate as long as 3.42 mm, as well as the mode width keeping as 1.64 mm, a better one compared with the fixed refractive index. Considering its nanoscale dimen-sion and outstanding performance, the structure is easily realized when connected with electrodes..
Chinese Optics Letters
- Publication Date: Aug. 27, 2014
- Vol. 12, Issue 9, 092402 (2014)
Scattering
Calculation and analysis of Mueller matrix in light scattering detection
Keding Yan, Shouyu Wang, Shu Jiang, Liang Xue, Yuanyuan Song, Zhengang Yan, and Zhenhua Li
A new criterion for target detection and identification is proposed to realize metal/dielectric identification and recognition based on Mueller matrix analysis. By using randomly rough surfaces as targets, numerical calculations are used to prove the robustness and accuracy of the criterion. Moreover, to the best of ouA new criterion for target detection and identification is proposed to realize metal/dielectric identification and recognition based on Mueller matrix analysis. By using randomly rough surfaces as targets, numerical calculations are used to prove the robustness and accuracy of the criterion. Moreover, to the best of our knowledge, this is the first time to successfully explain the criterion by theoretical analysis. We believe the work provides an important reference for polarization imaging in laser radar and remote sensing, and so on..
Chinese Optics Letters
- Publication Date: Aug. 22, 2014
- Vol. 12, Issue 9, 092901 (2014)
Using fence pulses to suppress stimulated Raman scattering effect in laser–plasma interaction
Yuliang Zhou, Zhan Sui, Yuanchao Geng, Lixin Xu, and Hai Ming
In inertial confinement fusion, the laser–plasma interaction (LPI) happens when the high-energy laser irradi-ates on the target where the scattered light share generated from the stimulated Raman scattering (SRS) effect is difficult to suppress. We propose a method using fence pulses (FPs) to suppress the backward SRS In inertial confinement fusion, the laser–plasma interaction (LPI) happens when the high-energy laser irradi-ates on the target where the scattered light share generated from the stimulated Raman scattering (SRS) effect is difficult to suppress. We propose a method using fence pulses (FPs) to suppress the backward SRS by inhibiting the growth of the intensity of electron plasma waves. Based on our simulation, the FPs can weaken SRS effect in the LPI effectively..
Chinese Optics Letters
- Publication Date: Aug. 22, 2014
- Vol. 12, Issue 9, 092902 (2014)
Spectroscopy
Equilibrium between NO3- and NO2- in KNO3–NaNO2 melts: a Raman spectra study
Xianwei Hu, Zongxin Yu, Bingliang Gao, Zhongning Shi, Jiangyu Yu, and Zhaowen Wang
We study ionic structure of KNO3–NaNO2 melts under air atmosphere by using Raman spectroscopy. Molar fraction of NO3- and NO2- is obtained and thermal stability of this kind of melts system is then analyzed. The results show that when the temperature is increased to a certain value, equilibrium between the decom-positiWe study ionic structure of KNO3–NaNO2 melts under air atmosphere by using Raman spectroscopy. Molar fraction of NO3- and NO2- is obtained and thermal stability of this kind of melts system is then analyzed. The results show that when the temperature is increased to a certain value, equilibrium between the decom-position of NO3- and the oxidation of NO2- exists in KNO3–NaNO2 melts. When temperature is higher than 644 K, the molar fraction of NO3- decreases a little with temperature increasing for the melts in which the initial fraction of KNO3 is 90 wt%, but for the melts in which the initial fraction of KNO3 is 10–80 wt%, the molar fraction of NO3- increases with temperature, and the increasing rate is slower for a higher initial frac-tion of KNO3. Molar fraction of NO3- increment increases linearly with initial fraction of NaNO2. The sample in which the initial fractions of NaNO2 are 11.3 and 14.5 wt% under air atmosphere shows the best thermal stability at 762 and 880 K, respectively..
Chinese Optics Letters
- Publication Date: Aug. 26, 2014
- Vol. 12, Issue 9, 093001 (2014)
X-Ray Optics
Multi-energy four-channel Kirkpatrick–Baez microscope for X-ray imaging diagnostics at the Shenguang-II laser facility
Shengzhen Yi, Baozhong Mu, Xin Wang, Li Jiang, Jingtao Zhu, Zhanshan Wang, Pengfei He, Zhiheng Fang, Wei Wang, and Sizu Fu
A four-channel Kirkpatrick–Baez microscope working at multiple energy bands is developed for multiframe X-ray imaging diagnostics at the Shenguang-II laser facility. The response to the multiple energy bands is realized by coating the double-periodic multilayers on the reflected surfaces of the microscope. Because of tA four-channel Kirkpatrick–Baez microscope working at multiple energy bands is developed for multiframe X-ray imaging diagnostics at the Shenguang-II laser facility. The response to the multiple energy bands is realized by coating the double-periodic multilayers on the reflected surfaces of the microscope. Because of the limited size of the microstrips in the X-ray framing camera, the image separation is controlled by the conical angle of the reference cores during microscope assembly. This study describes the optical and multilayer design, assembly, and alignment of the developed microscope. The microscope achieves a spatial resolution of 4–5 mm in the laboratory and 10–20 mm at Shenguang-II laser facility within a 300 mm field of view. The versatile nature of the developed microscope enables the multiple microscopes currently installed in the laser facility to be replaced with a single, multipurpose microscope..
Chinese Optics Letters
- Publication Date: Aug. 23, 2014
- Vol. 12, Issue 9, 093401 (2014)
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