Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences
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Temperature-Insensitive Frequency Conversion by Electro-optic Effect Compensating for Phase Mismatch
No full textA universal phase mismatch compensation method, which can be applied to temperature-insensitive frequency conversion, is experimentally demonstrated. In this method, two nonlinear crystals and an electro-optic crystal are cascaded. The generated phase mismatch in the nonlinear crystal can be well compensated for in the electro-optic crystal, thereby improving the stability of frequency conversion. In the proof-of-principle experiment, temperature-insensitive second and third harmonic generation (SHG and THG) are investigated by cascading KH2PO4(KDP) and KD2PO4(DKDP) crystals. The experimental results show that the temperature acceptance bandwidths of SHG and THG are 2.1 and 2.3 times larger, respectively, than that of the traditional method employing a single crystal. Meanwhile, the effectiveness of this method is also analyzed at a high power density, and a solution for the case of a nonuniform temperature is also discussed. Furthermore, angle-insensitive SHG is demonstrated to prove that this method can significantly reduce the influence of various unfavorable factors on frequency conversion. The demonstrated method may have potentially important applications in the nonlinear optical frequency conversion system. ? 2016 IEEE
Total internal reflection orders in transmission grating
No full text当前高功率激光装置系统中, 国内使用透射式衍射光栅进行光束采样, 国外甚至使用光栅聚焦并同时结合谐波分离和采样功能. 高功率激光辐照下, 除了0级透射打靶光以及目标取样光外, 其他级次衍射光的影响也不可忽视, 可能造成诸如鬼像聚焦破坏、时间脉宽测量不稳定、近远场测量噪声等问题. 尤其是透射衍射光栅内部全反射级次会导致光栅出射一系列规律的衍射花样, 造成上述干扰和危害. 首先理论上针对透射式光栅(包括取样光栅和聚焦光栅)进行了相应的计算和分析, 然后从实验上观察并测量了取样光栅内部全反射级次的现象, 并且结Major Project of the National Science and Technology of the Ministry of Science and Technology of China [GFZX0205010405.2]; Young Scientists Fund of the National Natural Science Foundation of China [11204331]In a current high-power laser system, transmission grating has been used to sample, separate and focus laser beam. Under high power laser irradiation, besides the 0-order shooting beam and target sampling beam, the detrimental influence of other diffraction orders should be taken into consideration seriously. These useless orders may damage other nearby optical elements and mechanical devices, disturb and confuse the measurement of time pulse and near/far-field intensity. Especially the total internal diffraction order will lead to some series diffraction patterns, causing the above problems. First, relevant theoretical calculation and analysis are carried out for transmission grating (including beam sample grating and focusing grating), which can predict and indicate these inconspicuous diffraction orders. These orders appear on four receiving screens regularly and periodically, and the periodic distance between them is determined by ray-tracing draft. Second, the phenomenon of total internal reflection order is observed and measured by combining with anti-reflection film. The measured periodic spacings on three screens are 24 mm, 26 mm and 35 mm, respectively. Moreover, energy intensities of these redundant orders are measured finely, which shows that their contrasts or SNRs to 0-order main laser is in a range of 10(-8)-10(-4)). Finally, some appropriate and effective approaches to eliminating or avoiding total internal reflection and other useless orders are proposed and discussed, which include 1) coating by anti-reflection film with pre-deep etching; 2) optimizing the grating design to make redundant orders far from target spot; 3) placing laser scattering or absorbing devices at corresponding position to avoid being damaged by the side-leakage energy and ghost image of total internal reflection and other redundant orders
Attenuation of high rate in parameter measurement of high power laser
No full text在高功率激光参数测量中,高倍率衰减方案设计是空间分布测量的关键。分析了远场测量光学系统,将95%环围能量直径作为评价远场测量系统的重要指标,明确了高倍率衰减对远场测量结果的影响,确立了高倍率衰减方案的设计原则。利用Virtual Lab软件,针对单个平板、成对平板、成对楔板三种常见的高倍率衰减方案,分析了衰减片摆放角度、位置、厚度、成对衰减片间距等因素对于远场测量系统的影响。针对焦距3 000 mm,F数为10的缩束系统,考虑杂散光对于远场测量的影响,优化得出最佳高倍率衰减方案。该方案下,远场像面处95%In high power laser beam parameters measurement, attenuation scheme with high rate is key to far-field measurement. The far-field optical measurement system was analyzed and diameter of 95% encircled energy was used as important evaluation criterion of far-field measurement system. Measurement error of far-field optical measurement system and effect of attenuation with high rate on far-field measurement results were analyzed. Principle of attenuation scheme with high rate was established. By changing parameters of high attenuation rate in condition of single parallel plate, a pair of parallel plates and a pair of wedge flaps by Virtual Lab, influence of attenuation on the far-field measurement system was simulated and analyzed deeply. According to measurement system for f =3 000 mm and F =10, best attenuation scheme with high rate is designed. Diameter of 95% encircled energy of far-field image is 45.5 μm, or 3.54 times of diffraction limitation. ? 2016, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved
Single-shot isolation-rate measurement for large-aperture faraday rotator
No full text搭建了全光纤化的大口径磁光隔离器隔离度单次测量系统,体积小且调节灵活方便,在大口径隔离器的在线测量方面具有独特优势。利用光纤器件在光束传输和耦合方面的优势以及磁光隔离器的工作特点,采用透过率相对测量法和静动态对比法实现了隔离度的单次测量。实验可测量动态范围达到33dB以上,且通过调整光纤耦合器分光比可使测量动态范围进一步提高到50dB以上。该方法有效消除了输入信号脉冲功率及偏振态抖动等因素对测量精度的影响,在输入信号脉冲能量和偏振态随机抖动的情况下,仍然可实现抖动波峰波谷(PV)值为2.2%的测量精度。中国科学院青年创新促进会资助课题An all-fiber Faraday rotator isolation rate measurement system is designed and realized. The system has tremendous advantage for large aperture Faraday isolator on-line measurement due to its flexible alignment and more compaction. Employing the method of relative transmission measurement and transmissions contrasting between static and operating states, single-shot isolation-rate measurement is achieved. The available measurement range larger than 33 dB is demonstrated experimentally. And the potential to get measurement range larger than 50 dB by adjusting the coupling rate of the fiber couplers is affirmed. Measurement accuracy of 2.2% of PV value is achieved even while keeping the input pulse energy and polarization in random vibration, which illustrates that the influence of the input pulse energy and polarization vibration on the measurement accuracy is eliminated. ? 2016, Chinese Lasers Press. All right reserved
Ammonium-crown ether supramolecular cation-templated assembly of an unprecedented heterobicluster-metal coordination polymer with enhanced NLO properties
No full textNational Natural Science Foundation of China [51432006, 50925207, 51172100]; Ministry of Science and Technology of China [2011DFG52970]; Ministry of Education of China for the Changjiang Innovation Research Team [IRT14R23]; 100 Talents Program of CAS; JiaAn ammonium-crown ether host-guest supramolecular cation-templated synthetic methodology has been developed to construct a structurally unprecedented heterobicluster-metal coordination polymer (HCM-CP 1) based on tetranuclear clusters [WS4Cu3](+) with different connection environments, pentanuclear clusters [WS4Cu4](2+), and Cu+ building metal ions. HCM-CP 1 exhibits enhanced NLO properties, which may be ascribed to the incorporation of diverse building cluster components
Diffusion of metal ions from a substrate into oxide coatings
No full textNational Natural Science Foundation of China (NSFC) [61405225]Concentrations of metal ions from a substrate were found in coatings adjacent to the substrate by studying the coatings using X-ray photoelectron spectroscopy before and after annealing. Small metal ions easily diffused into the coating from the substrate, whereas larger metal ions had more difficulty doing so because of their large atomic radii. A higher annealing temperature and a lower packing density induced a faster diffusion rate and a higher concentration of metal ions in the coating. Smaller metal ions passed through a SiO2 layer and preferentially accumulated in the Ta2O5 layer due to the migration of oxygen vacancies. These results are relevant for selecting the coating temperature, annealing temperature, and the substrate. (C) 2016 Optical Society of Americ
Geometry Dependent Evolution of the Resonant Mode in ZnO Elongated Hexagonal Microcavity
No full textNSFC [61378074, 61108059, 11404063]; Shanghai Rising-star Program [14QA1404000]; Shanghai Science and Technology Committee [14PJ1401200]We have developed a novel but simple approach to obtain ZnO microcombs with parallelogram stems and elongated hexagonal branches. We found that the present elongated hexagonal microcavity exhibited quite different features for its optical resonant modes due to the broken hexagonal symmetry. The resonant mode evolution of such microcavity was investigated systemically by using a spatially resolved spectroscopic technique. Theoretical analyses based on the plane wave mode and FEM simulations agreed well with the experimental results. We believe that our research allows us to have a deeper understanding of the controllable growth of novel optical cavities and the shape-dependent optical resonant modes
High Verdet constant of Ti-doped terbium aluminum garnet (TAG) ceramics
No full textNIFS Collaboration Research program [NIFS13KBAH006]; JSPS [15K18207, 26709072]; AMADA foundation; NSFC [61475172]The temperature dependence of the Verdet constant of a 0.8 at % Ti-doped terbium aluminum garnet (TAG) ceramics was investigated using lasers with wavelengths of 632.8 and 1064 nm. A high value of the Verdet constant was obtained at 296 K - namely, 184 and 53 rad/Tm for 632.8 and 1064 nm, respectively. The Verdet constant of the Ti:TAG ceramics at 1064 nm is about 1.5 times higher than that of the terbium gallium garnet (TGG) ceramics. The transmittance of this sample was about 75% at the wavelength of 1 mu m. This material represents a possible candidate for next-generation devices that utilize the magneto-optic effect. (C)2015 Optical Society of Americ
Multi-walled carbon nanotubes covalently functionalized by axially coordinated metal-porphyrins: Facile syntheses and temporally dependent optical performance
No full textNational Natural Science Foundation of China [51432006, 50925207, 51172100]; Ministry of Science and Technology of China [2011DFG52970]; Ministry of Education of China [IRT14R23]; Ministry of Education; State Administration of Foreign Experts Affairs [B13Axially coordinated metal-porphyrin-functionalized multi-walled carbon nanotube (MWCNT) nanohybrids were prepared via two different synthetic approaches (a one-pot 1,3-dipolar cycloaddition reaction and a stepwise approach that involved 1,3-dipolar cycloaddition followed by nucleophilic substitution), and characterized through spectroscopic techniques. Attachment of the tin porphyrins to the surface of the MWCNTs significantly improves their solubility and ease of processing. These axially coordinated (5,10,15,20-tetraphenylporphyrinato)tin(IV) (SnTPP)-MWCNTs exhibit significant fluorescence quenching. The third-order nonlinear optical properties of the resultant nanohybrids were studied by using the Z-scan technique at 532 nm with both nanosecond and picosecond laser pulses. The results show that the nanohybrids exhibit significant reverse saturable absorption or saturable absorption when nanosecond or picosecond pulses, respectively, are employed. Improvement in the nanosecond regime nonlinear absorption is observed on proceeding to the nanohybrids and is ascribed to a combination of the outstanding properties of MWCNTs and the chemically attached metal-porphyrins
An electrochemical bifunctional sensor for the detection of nitrite and hydrogen peroxide based on layer-by-layer multilayer films of cationic phthalocyanine cobalt(II) and carbon nanotubes
No full textNational Natural Science Foundation of China [51002046, 51102082, 51202061, 21573062]; Natural Science Foundation for the Natural Science of Heilongjiang Province of China [LC2012C02, B201308]; Research Fund of Heilongjiang Provincial Education DepartmentAs vital biological mediators, the accurate detection of nitrite (NO2-) and hydrogen peroxide (H2O2) is desirable for clinical monitoring and diagnosis. Herein, cationic 2,9,16,23-tetra[4-(N-methyl) pyridinyloxy]-phthalocyanine cobalt(II) ([TMPyPcCo](4+)) and acid-treated multiwalled carbon nanotubes (aCNTs) were alternately self-assembled on the glassy carbon electrode (GCE) by means of the electrostatic interaction, leading to a 3D loose and interconnected assembly of [TMPyPcCo/aCNTs](n) multilayer films. In the [TMPyPcCo/aCNTs](n) films, [TMPyPcCo](4+) is anchored onto the surface of aCNTs without any inert polymer binders, which is beneficial to expose more active sites for electrocatalysis. The effective combination of [TMPyPcCo](4+) and aCNTs brings many advantages in electrochemical detection, involving the fast oriented transmission of charges, permeable channels for ion adsorption and transport, and more sensing sites, thus the [TMPyPcCo/aCNTs](n) films display excellent electrochemical sensitivity towards both NO2- and H2O2. The responses of NO2- and H2O2 vary linearly with respect to the concentration from 5 mM to 30 mM and 10 mM to 9 mM. Furthermore, the superior cycling stability, reproducibility, and selectivity make [TMPyPcCo/aCNTs](n) films suitable for the real samples