Ordinary silica fibers are easy to break in real applications due to their characteristics of brittleness. Plastic optical fibers were proposed to replace silica fibers in crack monitoring. Moreover,considering the uncertainty of crack propagation direction in composite materials,the influence of the angles between plastic optical fibers and cracks was studied. A set of plastic optical fiber sensing device was designed and the relationship between optical loss and crack width under different fiber/crack angles was measured through the device. The results show that the optical loss in plastic optical fibers increased gradually with crack propagation. Therefore,applying plastic optical fibers in crack monitoring is feasible and the sensitivity of plastic optical fiber crack sensors decreases with the increasing of fiber/crack angles. Moreover,from the experimental results,the maximum optical loss of 0.5mm plastic optical fibers is 78.76 μW,while the maximum optical loss of 0.25 mm plastic optical fibers is only 24.28 μW. Therefore,the fibers with bigger diameter have more bend loss when they are bent.

A compact optical fiber sensor based on a Mach-Zehnder interferometer embedded in fiber Bragg grating was proposed and experimentally demonstrated. The Mach-Zehnder interferometer is realized by concatenating two spherical-shape structures separated by a middle section. The spherical-shape structures act as a mode splitter and a mode collector,respectively. The effects of different structure parameters of Mach-Zehnder interferometer were discussed. As a result,the resonant wavelength of the fiber Bragg grating and the interference dip of the Mach-Zehnder interferometer have the different sensitivities of temperature,refractive index and liquid level. Experiment results show that the sensitivities of interference dip of Mach-Zehnder interferometer to temperature,refractive and liquid level are 0.072 4 nm/℃,87.65 nm/RIU and －0.029 714 nm/mm,respectively,the resonant wavelength of the fiber Bragg grating has sensitivity of 0.009 89 nm/℃ to temperature,while is insensitive to refractive index and liquid level. The simultaneous measurement of dual parameters can be realized by sensitive matrix. This kind of sensor will have wild applications in chemistry,biology and pharmacy.

A scheme to measure the temperature distribution based on Brillouin optical correlation reflectometry was proposed according to the dependence of the Brillouin frequency shift on the temperature in the optical fiber. The white Gausssian noise signal was utilized to modulate the laser because of the non-periodicity of the noise,which could resolve the problem of the trade-off between the measurement range and the spatial resolution existed in conventional Brillouin optical correlation reflectometry systems. The experiment of temperature measurement was demonstrated in 253 m standard single-mode optical fiber,with spatial resolution of 54.6 cm and temperature accuracy of ±1.07℃.

Based on the formation and attenuation mechanisms of Fiber Bragg Gratings (FBGs),a model describing its attenuation law was established to study the effect of environmental temperature on its service life. This model discusses physical mechanisms of formation and change of the refractive index modulation,gives the relation of peak reflectivity between temperature and time. By experiment and numerical simulation,the rationality of theoretical model is verified. It is concluded that FBGs can work reliably for a long time under conventional conditions without consideration effects of other environment impacts except the temperature.

In the distributed Raman optical fiber temperature measurement system,Anti-Stokes light and Stokes light have different propagation speeds due to the fiber dispersion effect,this will cause mismatch of the acquisition signals,resulting in measurement error. A method was proposed to use the piecewise cubic Hermite interpolation algorithm to correct the Anti-Stokes signal,eliminating signal mismatch and reducing the system measurement error. The method is verified on our 1 km sensing prototype. Before correction,the Anti-Stokes signals have one point more than the Stokes signals,causing －7.45% error at front of the temperature peak. After interpolation correction,the signal mismatch is eliminated,resulting in the system measurement error within ±1.5%.

The scheme of multipath interference reduction based on filter and isolation technology and the scheme of nonlinear coefficient reduction based on hybrid-type optical fiber technology were proposed,which can overcome self-excited phenomenon of remote pumped optical amplifier system with channel associated structure using the traditional 2nd-order pump. Filter and isolation technology can improve multipath interference by placing the filter and isolation unit in the fiber lines. Hybrid structures of ordinary fiber and large effective area fiber can reduce the nonlinear effect when using hybrid-type optical fiber. Theoretical analysis draw a conclusion that multipath interference can be reduced by decreasing multiple reflections of the pump,and nonlinear coefficient can be reduced by increasing the effective area of fiber. The experimental results show that unit the pump power accessed to the remote gain unit is increased by 1.2 dB using filter and isolation unit,and 1 dB using hybrid-type fiber structure with 20 km EX2000 fiber and 80 km G.652 fiber. The research contributes to the realization and application of reducing the effects of self-excited of second-order pump with channel associated structure.

A compact binocular stereo vision system was used for measurement in small scale. This paper analyzed the influence of CCD pixel discontinuity on the measurement accuracy and then built the relationship between structural parameters (baseline,focal length and object distance) and distance measurement errors. When considering the discontinuity of pixels,the relationship curve about measuring distance and disparity was of a stair-step shape. The measurement error decreased with the increase of the baseline and the focal length,while it gradually increased along with the object distance. The measurement accuracy of our system can reach 98.89%. Our valuable theory can be offered for optimization design of the binocular stereo vision system which is applied in small scale measurement.

Traditional N-FINDR algorithm suffers from complicated calculations,and is sensitive to noise and initial endmembers,resulting in wrong extraction by outliers. In order to solve these problems,an improved fast N-FINDR endmember extraction algorithm was proposed,which gets rid of the redundant information and reduces the search area of commonly used N-FINDR algorithm by spectral distance,then smoothes the spectral noise and gets rid of the outliers adaptively. In addition,the initial endmembers of N-FINDR are selected by maximizing the spectral distance,avoiding the blindness of random selection. The synthetic data and real hyperspectral data were used for simulation analysis,and the proposed method was compared with existing algorithms. The experiment results show that the proposed method is able to extract the endmembers correctly in the noise,and has higher extraction efficiency and robustness than existing algorithms.

Based on the mathematical model of light intensity distribution in multi-beam interference field,the patterns have been calculated and stimulated respectively for two beams,three beams and four beams interference exposure,in the case of having incidence angle errors and unequal intensity of each beam. The stimulated results have been analyzed and compared with that in ideal situation. The study results show that angel deviation of incident beam mainly affects the shape and period of interference pattern,and inequality of light intensity of each incident beam is the main factor that leads to decrease of pattern contrast. The multi-beam interference lithography experiments have been done by using a laser source with the wavelength of 402 nm. Under the conditions of 32 mW laser output power and 16° angle between two incident beams,by controlling exposure dose and development process,the gratings,dots and holes array with the period of about 1.4 μm have been generated by two-beam interference lithography,and the hexagon array with the period of about 1.7 μm have been got by three-beam interference lithography. The results provide some theoretical reference for fabricating micro-nano periodic structures and improving the quality of pattern by multi-beam interference lithography technology.

By analyzing the diurnal variations in monthly variation on temperature,humidity,refactive index structure parameter,pressure and visibility at the hight of 8.0 m above ground in surface layer in arid area,the probabilistic characteristics of atmospheric extinction and atmospheric turbulence were obtained. Based on the analyzed data,the possible effecs on a special case of laser propagation in arid area are discussed under the condition that the laser wavelength is 1.06 μm and the propagation length are 1 000 m and 3 000 m respectively. The results show that the extinction coefficient of diurnal variation change little ups and downs. The extinction coefficient of each month in January during winter is the largest,the extinction coefficient in July during summer is the smallest,and the difference of the two is about twice. The average transmittance of 1 000 m is about 1.16 times that of 3 000 m. The turbulence strength in January is the weakest month,and April in spring and October in autumn have stronger turbulence strength. The average turbulent influence of 3 000 m is about 1.95 times that of 1 000 m. The best propagation effect is the best at 21∶00 in July of summer. The mean intensity distribution of different propagation distance have different probability density.

In order to research high-power multi-position-pumped fiber lasers,the theoretical analysis was presented based on the rate equations and boundary conditions of Yb-doped double-clad fiber lasers. All-fiber laser is built with the self-made cascaded couplers. In the experiment,the pump efficiency of a single coupler is 96%,pump transmissiom loss is 10%,signal loss of the couplers are 0.87 dB and 0.18 dB respectively. In the structure of linear cavity,the optical conversion of forward pump is 69%,lower to the backward pump of 70% optical conversion,consistent with theoretical simulations; in the two-end pump,single input pump power of 975 nm is 110 W,the output power is 311 W with the central wavelength of 1 080 nm,spectral width is 1.6 nm,the optical-optical conversion is 70%,M2～1.3. The results have shown that the output power of laser will continue to increase with the increase of the pump power or the number of couplers.

Via investigation on the evolution of fluorescence intensity in quenching process,it is discovered that the absorption distribution of exciting light can influence the fluorescence intensity in a potential way when the inner filter effects occur. According to the impact mechanism of absorption distribution on fluorescence intensity,a correction method based on fluorescence response function for removing the influence of absorption distribution is proposed. Photo induced fluorescence quenching of Quinquethiophene / fullerene (C70) at different excitation wavelength is tested to inspect the correction effect. Experimental results demonstrate these quenching efficiencies obtained without correction on the influence of absorption distribution weakly correlated with the absorption spectrum of C70,while the corrected ones are independent of them. Which means further correction on absorption distribution can effectively improve the final correction accuracy in fluorescence quenching analysis.

In order to clarify and evaluate the effect of pulsed electric field on drought resistance of maize during germination and its mechanism based on living cells,the －0.1 MPa osmotic potential of PEG-6000 solution was used to form drought stress,the effect of pulsed electric field treatment with field strength of 100 kV/m,width of 80 ms,pulse frequency of 1 Hz on spontaneous luminescence and delayed luminescence from germinating corn seeds under drought stress were studied. The results show that the spontaneous luminescence and delayed luminescence integrated intensity gradually increase during the germination process of corn and decrease cased by the spontaneous luminescence,pulse electric treatment makes delayed luminescence integrated intensity of germinating corn under drought stress increase,the changes of the spontaneous luminescence and delayed luminescence integrated intensity are same as the changes of the germination drought index and the storage material transport rate of germinating corn. These results indicated that the treatment of pulsed electric fields improves drought tolerant of germination corn. The changes of the spontaneous luminescence and delayed luminescence integrated intensity of germinating corn reflecte the effect of pulsed electric field treatment on the drought resistance of germinating corn from cell metabolism and cell damage respectively. The research results reveal the mechanism of pulsed electric field on the drought resistance of germinating crop seeds,and provide a reference for development of agricultural technology based on pulsed electric field.

The relationship between the ellipticity of point spread function and the focal length of cylindrical lens was investigated. Fluorescent inverted microscopey imaging system is based on Olympus IX-83. With three different focal length,the point spread function with custom built stochastic optical reconstruction microscopy instruments was measured. A method to evaluate the cylindrical lens was developed based on linear region and localization error. The results show that linear region of 1μm and axial localization error of 16 nm can be achieved with correct focal length. As the demonstration,three dimension super-resolution image of Actin filaments was reconstructed.

The Spearman′s correlation coefficients between various fabrication errors and functionalities were analyzed on a 3-belt phase-only pupil-filter. Three kinds of pupil-filters with different numbers of belts were compared to identify the influence of eccentricities of different belts. The correlation coefficients between eccentricity and the radius at half central intensity and Strehl ratio are both greater than 0.8,and rounding can cause the intensity of the first order sidelobe changing up to 29.04%,thus these two parameters are identified as the significant geometrical parameters. Besides,the eccentricities of outer belts affect the super-resolution performance more significantly than inner belts,therefore they need to be controlled with tighter tolerances. This method provides a theoretical foundation and a versatile technical route for the effective specification in design and manufacturing of micro-optical elements.

In order to meet the demand of lightweight,miniaturization,large fields of view,a multi-focusing artificial-compound-eye with a gradually decreasing focal length was proposed. The ommatidia were arranged in the form of concentric circles,and each one owned the same focal length in the same circle. The artificial-compound-eye was fabricated by the photoresist reflow method. Each ommatidium had a specific focal length within a small interval through the calculation of dosage of photoresist,so that all the ommatidia could focus on the same plane. As for the manufacturing process,negative pressure was applied to solve microlens deformation problems,and Polydimethylsiloxane coelomic compartment was used for injecting optical adhesives without any impurities. In addition,Norland81 as the moulding material has similar qualities to the previous one,yet it can be cured 3 to 5 times faster. The simulation model was established by ZEMAX,and the result of ray-tracing shown that a clear image point could be obtained even under large field of view.

An ultra-thin direct-down LED panel model with tapered optical elements was proposed to cover the shortcomings of large thickness and light density of the direct-down LED panel light. The diffuse reflection backboard and the reflective cone structure in this model can increase the LED light mixing distance and improve light uniformity. Using the idea of dividing unit,a hexagonal light source is used as a unit to study in Taguchi method by designing orthogonal experimental group. With the Tracepro software simulation,the five factors influencing light uniformity and efficiency are taken into consideration,including the radius on upper and lower surfaces of the truncated cone element,thickness,height and LED spacing of the hexagonal light source. Apply ANOVA theory to analyze the impact of those factors on the quality,then optimize the structure parameters of the light. And ultimately,a direct-down LED panel light with the thickness of only 15 mm,the light uniformity up to 95.3% and the light efficiency up to 92.97%,are designed.

To correct the static and dynamic aberrations introduced by a toroidally shaped conformal window on an aircraft across the full field of regard,a static corrector configuration was designed. The corrector is composed of three tilted and decentered elements with rotationally symmetric structures,and the surface of each element is aspheric. The corrector is fixed in position relative to the conformal window and its structure is compact and stable. Based on the vector aberration theory,the optical design of the corrector was presented and the aberration correction principle of the corrector was explained. The results show that,at any field of regard angle,the vectorial astigmatism introduced by the conformal window and the corrector are offseted mutually,and the static and dynamic astigmatism introduced by the conformal window across the full field are corrected. The wavefront aberration of the conformal optical system is less than one wavelength at the visible spectrum,and the modulation transfer function values of the system are above 0.8 at 50 lp/mm.

A multifunctional optical system for solar simulators,which could achieve collimating and divergent sunlight simulation simultaneously,was designed. The design of condensers used in the optical system,and the optimization techniques of optical integrators were described. The parameters of the optical integrator was optimized with both the sequential and non-sequential functions of Zemax software. Also the collimator objective was designed. According to the analog simulation results of the optical system with LightTools,when the collimating sunlight simulation was achieved in the designed optical system,the irradiated surface reached Φ300 mm,and the irradiation nonuniformity superior to ± 6.1%; when the divergent sunlight simulation was achieved by changing the position of collimator objective,the irradiated surface could reach Φ1 500 mm and the irradiation nonuniformity superior to ± 6.7%.

The propagation properties of the guided modes were studied in a taper slab waveguide with anisotropic metamaterials. For TM oscillating guided modes,the dispersion and power flux equations were obtained from the Maxwell’s equations. The transmission and reflection coefficients of TM0 mode in a taper slab waveguide with anisotropic metamaterials were investigated. Through the dispersion,transmission and reflection equations,some related characteristic curves were received. These curves show that the transmission coefficient ct2 decrease as the electromagnetic wave transmission,it begins oscillating near zero,and appears double-mode reflection. The first reflection coefficient ar12 increases from zero,then it approaches a fixed value. And for the second reflection coefficient ar22,it increases from zero to near 1 monotonously. Besides,with the increase of the frequency of electromagnetic waves or metal filling ratio in the multi-layer structure,the curves of transmission coefficient move down,which reveals that the transmission in the waveguide decreases. For the first reflection,the curves moving down means the reflection for electromagnetic waves decrease. However,for the second reflection,the curves moving up means the reflection for electromagnetic waves increase.

A method for the long-term stability improvement of an optoelectronic oscillator was proposed,which is based on a feedback control loop. To achieve the long-term stability,the frequency of optoelectronic oscillator is measured with a field programmable gate array and a frequency dividing circuit. Then the length of optoelectronic oscillator loop is adjusted with a fiber delay line. The accuracy of dividing method to measure the frequency of optoelectronic oscillator is discussed in theory. An experiment based on a single loop structure shows that the phase noise performance does not deteriorate while the long-term stability of optoelectronic oscillator is effectively improved,and the frequency stability of optoelectronic oscillator with feedback control loop is ±0.8 ppm over 7 hours.

A composite optical isolator of one-dimensional magneto-photonic crystals was presented. The 4×4 transfer matrix method used to investigate the optical isolation property of this isolator. When the angel between applied magnetic field and optical axis of optical path is 19.95°,with the total thickness of 20.16 μm,it can realize the optical isolation around 3.1 nm. When the incident angle is 3.9°,it can also realize the optical isolation around 1.06 nm with flat-top responses. The structure can realized broadband isolation,flat-top responses and has great tolerance of incident angle at the same time. It has a high valuation in practical application.

To improve the system resolution of the surface plasmons resonance,a surface plasmons resonance incentive model based on the five-layer structure was proposed which is prism base-silver-dielectric layer1-dielectric layer2-environment media. Silver film and double dielectric layers composed the composite resonance film. According to the thin film optics and waveguide theory,the effect of the double dielectric layer on the incentive mechanism and modulation characteristics of the surface plasmons resonance was discussed. Numerical simulation was conducted on the resonance spectroscopy of the double dielectric layers structure by finite element analysis method. The simulation result shows that,the full width half maximum of the double dielectric structure is about 0.1 times narrower than traditional prism surface plasmons resonance when the refractive index of analyte is same. The resolution of the double dielectric layers structure is 5.4 times higher than the traditional prism surface plasmons resonance. The ethylene glycol was adopted as the sample detected,the quality factor and sensitivity of the refractive index sensor were analyzed. The quality factor can attain 465 and the sensitivity can attain 7.2°/RIU,which demonstrates the feasibility of the sensing structure. This structure provides a theoretical reference for the design of high resolution and high quality factor sensing system.

Considering the direct current drive electrical power from 0.5 W to 6.5 W on a different heatsink and the thermal resistance from 1℃/W to 30.5℃/W as optimization variables,a series of calculations are performed in order to obtain the target variables which are the objective function of luminous flux from 40 lm to 460 lm and correlated color temperature from 7 100 K to 8 600 K. The spectral power distribution of white light-emitting diodes was optimized using a combination of the photo-electro-thermal theory and multi- spectral power distribution modeling. When the objective function is close to 5%,the optimized results of SPD is obtained. The work provides a reference for practicing LED system designers to optimization an LED system.

As acquiring spectral response function by experimental method is always time limited and with a complicate process,a simulation of spectral response function and spectral resolution based on huygens point spread function was suggested. Taking into account the effects of optical aberration and diffraction,the fine spectral response function curves and spectral resolution at any nominal wavelength of the full spectral range can be calculated as early as in the design phase. A grating spectrograph with a spectral range from 1 000 nm to 2 500 nm was proposed for illustrating the simulation process. With a geometrical ray tracing method as a comparison,the spectrograph′s spectral response function at single wavelength and full spectral range are simulated by huygens point spread function method. The results demonstrate that the full width at half maximum of spectral response function acquired by huygens point spread function method is greater than the result of geometrical ray tracing method at any wavelength. The relative deviation changes from 2% to 5% for the full spectral range. Both optical aberration and diffraction affect the result of huygens point spread function method. At last,the comparison of spectral response function curves acquired by the two methods is shown with logarithmic scale for the y-axis. The results show that the effect of diffraction is dominant when relative response between 10－2 and 10－5 and can be neglected below 10－5. The uncertainty of the simulated process for the spectrograph with a 10nm spectral resolution is 0.025 nm.

A Shifted Dual Transmission Grating (SDTG) component has been designed and fabricated in this work,a range of 0.1~5keV time-resolved spectrum can be recorded when the SDTG coupled with a streak camera. This SDTG is composed of 2000 lines/mm and 5000 lines/mm sub transmission grating which shifted with a certain distance. One of this sub grating is designed to measure the soft X-ray spectrum in 100~1000eV photon energy while the other measures 1000~5000eV photon energy. This space-shifted grating can sufficiently use the limited recorded panel to obtain a spliced time-resolved spectrum in streak camera. In this paper,The SDTG component is calibrated to get the diffraction efficiencies on Beijing synchrontron radiation facility,and the related efficiencies was achived. According to the structure parameter of this grating,the absolutely diffraction efficiency value was enentually obtained in combination the experimental values with the rigorous coupled-wave anslysis,meanwhile a method is discussed to unfold the source spectrum from the obtained efficiency. This SDTG component can improve the performance of the spectrometer,and may become an outstanding device to precisely measure x-ray spectra in the diagnostics of laser-produced plasma.

In the Phosphate Buffer Saline buffer solution at PH 7.4,the fluorescence quenching characteristics of Bovine Serum Albumin when Ebastine existed were studied by Fluorescence spectra. After experiments,three quenching spectral curve groups were obtained under corresponding temperatures (298K,305K,312K). According to the Stern-Volmer equation,the quenching constants were calculated and then it was concluded: the quenching was belonged to static quenching mechanism. By calculating the thermodynamic parameters of the Ebastine-Bovine Serum Albumin system,it was shown that the binding power between Bovine Serum Albumin and Ebastine was mainly the hydrophobic force. By fitting the double logarithmic equation,the binding constants KA between Bovine Serum Albumin and Ebastine at three temperatures were obtained to be 3.27×104 L·mol－,4.11×104 L·mol－ and 7.59×104 L·mol－,respectively. The number of binding sites were 0.98,1.02,1.08. The binding distance between the donor (Bovine Serum Albumin) and the acceptor (Ebastine) was determined based on the Frster′s non-radiation energy transfer theory and it turned out to be 2.8 nm. The effect of Ebastine on the conformation of Bovine Serum Albumin was analysed by synchronous fluorescence spectra and three-dimensional fluorescence spectra.