The nonlinear optical absorption of CdSe/ZnS quantum dots in toluene with two different sizes are investigated using open aperture Z-scan with 6ns laser pulse at 532 nm. Nonlinear optical absorption of two samples display a switch over from saturation absorption (SA) to reverse saturation absorption (RSA) with increasing input laser intensity. When laser wavelength (532 nm) is smaller than the absorption peak (553 nm), it behaves two different SA processes which are related to different excited states at low intensity and RSA caused by excited state absorption (ESA) at high intensity. When laser wavelength is larger than the absorption peak (503 nm), it behaves SA related to one excited states at lower intensity and RSA caused by excited state absorption (ESA) and two photon absorption (TPA) at high intensity. Our results show that quantum dots are good candidate materials for the fabrication of optical switching and optical limiting device.

A serial of chalcogenide glasses with the composition of Ge28Sb6S(66－x)Sex(x=0, 10, 20, 30, molar fraction) are prepared by the melt-quenching technique. The densities, refractive indexes, VIS-NIR transmission spectra, IR transmission spectra and Raman spectra of the samples are measured respectively. The impact of the presence of Se on the physical and optical properties of Ge-Sb-S glass system are analyzed. The Raman spectra are used to discuss the relationship between structures and properties. Results show that with increasing Se content, the densities and refractive indexes of the samples increase, and the visible and IR cut-off edges shift towards longer wavelengths. The basic structural units of the pure sulfide glass are GeS4 tetrahedra and SbS3 pyramids. With the substitution of S by Se, the sulfur-selenide-containing samples present GeS4－xSex units and Se-Se homopolar bonds both in rings and in chains.

Random structures of silver dendriticlike cells, with the scale matching with infrared wavelengths, are prepared on the flexible conductive ITO film substrate, using the electrochemical deposition method by adjusting the experimental parameters. It is shown that the geometry of the silver dendriticlike structure can be fine-tuned by changing the concentration of PEG-20000, and, within certain limits, the branches of the silver dendriticlike structure get more exiguous with increasing PEG-20000 concentration. As a dielectric spacer, a PVA film with a certain-scale thickness is prepared and located on the silver dendriticlike cells by a vertical lifting deposition method. And a sandwich structural composite material is fabricated. The multiple passbands of infrared transmission spectra of the samples are gained, and left-handed effect is validated using a further slab focusing experiment.

Er3+-doped 80GeS2-10In2S3-10CsI(mol%)chalcohalide glass was fabricated by melt-quenching technique. The thermal stability, Raman spectra, absorption spectra, upconversion emission spectra of glass samples were measured, and upconversion mechanisms of Er3+ in the glass were analyzed. The intensity parameters(Ωt,t=2,4,6), spontaneous transition probabilities(Α), fluorescence branching ratios(β), and radiative lifetimes(τrad) were calculated by using the Judd-Ofelt theory. Under 980 nm diode laser excitation, intense emission bands centered at 526 nm and 549 nm corresponding to the transitions of 2H11/2→4I15/2 and 4S3/2→4I15/2 , respectively, were observed for the first time in this glass, and intensity of 549 nm green light is more stronger. For 549 nm emission band, the upconversion fluorescence lifetime is 0.34 ms, and the quantum efficiency is 69%. The dependence of visible emission intensities upon excitation intensity was examined. A plot of logIUP vs logIIR yields two fitted lines with slope 1.71 and 2.03, respectively, which indicates a two-photon process for green emission. Results suggest that Er3+-doped 80GeS2-10In2S3-10CsI chalcohalide glass may be a potential host material for upconversion green lasers.

Nanocrystalline ZrO2-Al2O3∶Er3+ luminescence powders are prepared by co-precipitation method. The room temperature sharp characteristics emissions of Er3+ ions are observed, in which green light at 547, 560 nm is the strongest. There exists the energy transfer between the matrix and rare earth ions Er3+. Samples with different sintering temperature are studied. The results show the samples with different sintering temperature display different crystalline phase. The up-conversion luminescence of nanocrystalline ZrO2-Al2O3∶Er3+ and ZrO2-Al2O3∶ Er3+/ Yb3+ are studied and the transition mechanism of the up-conversion are discussed. It is found that the red and green emissions of ZrO2-Al2O3∶Er3+ are two-photon process. In the up-conversion spectrum of ZrO2-Al2O3∶ Er3+ / Yb3+ the red and green emissions are also two-photon process, but very weak blue emission is the three-photon process. Concentration quenching of the ions Er3+ is discussed. The most appropriate doping concentration is 2%(Er3+/ Zr+4).

Random nanostructures of two-dimensional silver dendritic cells are prepared on the flexible Indium Tin Oxides film using the electrochemical deposition method at 0~2 ℃. The Polyvinyl Alcohol film, acted as a dielectric medium, is coated on the silver dendritic cells and combined with the uncoated cells face-to-face to fabricate a Ag/Polyvinyl Alcohol /Ag configuration. This dendritic nano-assembled Ag/Polyvinyl Alcohol/Ag configuration reveals a multiband resonance and different transmission peaks at optical frequencies, while the several contrast samples fail to show any transmission peaks at the same frequencies. The focused points are present when the wavelengths utilized are corresponding to the peaks of the transmission spectrum for the Ag/Polyvinyl Alcohol /Ag configuration.

In order to study the relation between the space between layers and the resonant frequency in periodic structures left-handed materials, the prism-shaped samples are produced as the spacing of 3.08 mm, 2.93 mm, 2.73 mm and 2.33 mm. The diagrams of the intensity and frequency are obtained by measuring the refraction of electromagnetic waves through the samples with HP8720ES scalar network analyzer. And the curves of the electromagnetic wave frequency and intensity are simulated of the spacing for 3.23 mm, 3.13 mm, 3.03 mm, 2.93 mm and 2.73 mm of prism-shaped samples.Experimental and simulation results are consistent, that is, the resonant frequency shifts from high frequency to low frequency with the decreasing space between layers.

Using Terahertz time-domain spectroscopy technology, the transmission spectra of polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethylene and acrylonitrile - butadiene - styrene are measured. Spectral characteristics of these five materials between 0.2~2.6 THz are studied.The absorbance and refractive index spectra of five plastic at room temperature in nitrogen atmosphere are obtained. The results show that refractive index and absorption coefficient of these five plastic are significant different,and the refractive indexes are in the ranges from 1.35 to 1.85. Compared to polyvinyl chloride and acrylonitrile-butadiene-styrene, the absorbance of polyethylene, polypropylene and polytetrafluoroethylene are much smaller. The research provides a method to identify plastic types and choose substrate of terahertz optical components using terahertz time-domain spectroscopy.

An asymmetric three-layer slab waveguide with a core of the left-handed material and sandwiched by two conventional materials is investigated. Considering the dispersive and an isotropic properties of the left-handed material, the dispersion equation and power fluxes for TE oscillating guided modes are obtained and mode dispersion curves are plotted,respectively, through Maxuell′s equations. Eight TE oscillating guided modes are found, including the fundamental mode. With the increase of mode number, mode dispersion curves move to right and the power flux curves move to right bottom. However, with the increase of waveguide thickness, mode dispersion curves move to left and mode power flux curves move up. Besides, all modes have abnormal dispersion properties and employ negative group velocities which reveals the special properties of the left-handed materials.

The role of total internal refection in photonic crystals multimode waveguides is studied, and the multimode interference situation and self-image using conventional coupled-mode theory are discussed and analyzed. The result shows that the input light still can be propagated with high efficiency down to multimode optical area, and resemble index-guided modes owing to the combination of total internal reflection and distribution Bragg reflection. A total internal reflection multi-mode interference photonic crystal waveguide polarization-insensitive power splitter is designed which has great potential value in the integrated optics.

The design and simulation of a new and high efficiency heterostructure beam splitter are proposed based on the coupling characteristics between the waveguide and ring resonator in two dimensional photonic crystals. The splitting properties of the beam splitter are numerically studied using the finite difference time domain method. By simply tuning dielectric constant of dielectric rods and inducing the redistribution of the power of the optical field, uniform or free splitting can be achieved. It is shown that a small dimension, a large separating angle and a high beam rate are extended to have more light output channels in the beam splitter at optical communication wavelength. These features of the proposed heterostructure ultracompact multiway beam splitter make it a promising candidate in optical communications application.

Based on transformation-optical approach, the distribution of permittivity and permeability for the elliptical concentrator is derived and functionality of the concentrator is numerically confirmed by the finite element solver COMSOL. The influence of the focus area and deviation of material parameters from perfect elliptical concentrator on the concentrating effect is studied. Results show that the smaller the focus area is, the stronger the total energy density is achieved; the performance of the concentrator is independent on loss tangent when it is less than or equal to 0.01. Besides, for the circular concentrator, the results in this paper are compared with the results of Rahm and validity of the proposed model is proven.

In order to solve the low external quantum efficiency of the GaN-based LED caused by the total reflection, which occurs at the semiconductor-air interface, the Monte Carlo and wave theory are applied to simulate based on the basic structure of the GaN-based LED with double gratings, and the impact of the main loss of photon on the extraction efficiency is analyzed. Through the numerical simulation, different grating groove depth, period, and the absorption coefficient are applied to analyze the dynamic effects of the LED light extraction efficiency. The results show that light extraction change as similar periodic cosin with the increase of grating groove depth, which is in accordance with the relationship between grating diffraction efficiency and grating depth; the perfect grating period is similar to the wavelength in GaN or ITO. The light extraction efficiency of traditional slab LED decrease slower than grating structure LED with the increase of GaN material absorption coefficient. The depth and period both in transmitted and reflected gratings are 350 nm, 300 nm, and 230 nm, 250 nm, respectively. When the light absorption coefficient of GaN value is 0, the maximum light extraction efficiency of 67% can be obtained, while the light extraction efficiency of traditional slab LED is 18.5%. The light extraction efficiency of GaN-based LED can be improved more than 3 times after being applied with double gratings. Light extraction efficiency can be enhanced more effectively by improving crystal quality and decreasing light absorption coefficient.

In order to resolve the low Er3+ concentration problem in Er3+ doped Si based light source, the Er2O3 films with high Er3+ concentration and strong 1.535 μm room photoluminescence are fabricated at 900 ℃ on Si(100) and SiO2/Si(100) substrates, respectively, by using the sol-gel spin coating method. Small thermal quenching of 1/5 is observed. PL intensity increases 2~3 times on SiO2/Si substrate compared with that on Si substrate. Er2O3 structure is single cubic. The Er2O3 films with strong PL intensity are promising candidates for application in Si-based light source and amplifier.

In order to solve the problem that traditional SPR theory is approximate when determining parameters of metal film based on Kretschmann geometry, the strict thin film optical theory is introduced. SPR attenuation curve is obtained with characteristic matrix of film system. The results show that there exists differences in resonance angle and amplitude of reflectivity between approximate SPR theory and thin film optical theory. Contour map of resonance angle deviation shows variation of resonance angle deviation under different dielectric constants of metal film. Further experimental study shows that the simulation result of thin film optical theory is more consistent with experimental data than of approximate SPR theory. Finally the sensitivity of SPR sensor is discussed using approximate SPR theory and thin film optical theory respectively, and as a result, there is great difference in distribution region of sensitivity. Optical parameters of metal film can be determined more exactly using thin film optical theory, and accurate parameter combinations must be benefit to design high sensitivity SPR sensors.

High brightness fiber coupling laser module with multi-linear-laser-diode-arrays is designed and fabricated.The laser diode chips are fabricated with a broad waveguide and double quantum well structure by molecular beam epitaxy method.The module contains 6 collimated single linear-laser-diode-arrays which can operate to CW 50 W output power with single emission width of 100 μm,pitch of 500 μm,cavity length of 1 200 μm and 19 emitters per bar.Beam output with high beam quality is obtained by space beam combination and beam shaping afterwards,the combined 6-beam output is focused into a 400 μm-core quartz fiber with NA0.22 by a set of flat-convex cylindrical lens.Finally,a maximum fiber end output power of 195 W with power density of 1.55×105 W/cm2 is achieved,and the total coupling efficiency is as high as 65%.

A compact,low cost,stable noncollinear optical parametric chirped pulse amplification system is studied,which is seeded by an Yb3+-doped self-starting passive mode-locked stacking pulse fiber laser centered at 1 053 nm.A gain higher than 1.1×107, single pulse energy exceeding 11 mJ with fluctuations less than 2% rms ,8 nm amplified signal spectrum are achieved.Different pulse durations of amplified signal are obtained by adjusting the stacker of the Yb3+-doped self-starting passive mode-locked stacking pulse fiber laser.

A novel miniature fiber-optic Fabry-Perot refractive-index sensor machined by 157 nm laser is proposed. The sensor head consists of a micro air F-P cavity near the tip of a single-mode fiber with a micro channel on the fiber tip. The micro channel is used as the entrance for medium under test. Two thin films are coated at reflective interfaces of the F-P cavity as mirrors to ensure high optical contrast, respectively. A RI resolution of 1 130.887 nm/ refractive-index unit is achieved by experiment. Compared with other fiber-optic RI sensors,the proposed sensor has a number of outstanding advantages including small,rigid,high resolution,excellent linearity,and wide measurement range,etc,which can meet the requirements for practical applications especially in biomedical diagnostic where small sensor size is essential.

For the compensation of the spherical aberration induced by refractive index mismatch in three-dimensional optical storage, the model of the optical storage is established, and the expression of the wavefront phase aberration function is achieved induced by refractive index with the storage depth. The phase aberration function is spred with Zernike polynomials. Under reading method of two-photon fluorescence and one-photon confocal fluorescence, the relation of the intensity with storage depth is obtained: under uncompensating the spherical aberration induced by refractive index mismatch, storage fluorescence intensity falls to zero in the storage depth of 200 μm; under compensating the first-order spherical aberration, the downtrend of storage fluorescence intensity with the storage depth is improved; under compensation the second-order spherical aberration, the storage fluorescence intensity varies little in the storage depth of 1 mm. And the method of the aberration compensation is analyzed in detail.

A 3D-SPECK in conjunction with ROI is applied to compress hyperspectral image sequences produced by the LASIS system.Firstly,the hyperspectral image sequences are decomposed with three-dimensional asymmetric DWT.Secondly,the Zero Block Tree is defined as codeunits.Then different coding rates are distributed to each codeunits in different regions (ROI or BG) to protect the hyperspectral information.Finally,the adapted 3D-SPECK algorithm is used to encode the codeunits individually.The numerical experiment results show that the PNSR is more than 40dB at 8:1 compression rate,and achieve the efficient protection of hyperspectral information.It is of lower computational complexity and higher real time performance,which can satisfy LASIS′s compression requirements.

Holographic storage properties and Ultraviolet-Visible absorption spectra of LiNbO3:Fe:Hf crystals adoped with Hf(4 mol%) are measured and analysised.Ultraviolet-Visible absorption edges obviously shift to long waveleng.The ratio of ［Fe2+］/［Fe3+］ increases with the increasing of ［Li］/［Nb］,which results in the deceasing of diffraction efficiency,and improving response speed and sensitivity.Moreover,the ability of light scattering resistance decreased with the increasing of ［Li］/［Nb］.It is contributed to the change of Fe2+Li concentration in crystals.

In order to overcome some disadvantages of the conventional computer tomography,such as multiple projection directions,complicated systems,the tomography reconstruction based on three projection directions is proposed.Algebraic Reconstruction Algorithm suitable for fewer views is selected and its revised method which can well improve reconstruction precision and restrain salt-pepper noise is applied.The iteration numbers impacting on image quality and velocity and the impact that different shapes of original images on the reconstruction image quality are analyzed and discussed.The simulation results are presented,which show that the stable reconstruction can be gotten after 300 iteration numbers,tomography reconstruction based on three projections can be well realized for the axis-symmetric objects.The analysis results can provide some theory instruction for the further work on digital holographic tomography based on three projections.

A hybrid encryption in the optical transform domain based on public key distribution system is proposed aiming at safely deliver and management of optical encrypted system.Frist,the original image is encrypted based on optical system,and then,the work key of optical system is compressed,finally,distribution and management of the compressed key is dong by public key distribution system.In the decryption stages,the receiver do not need to wait and can obtain dencryption key in advance by means of public key distribution system.The theoretical analysis and computer simulation results show that the proposed method can solve the problem of safely deliver and management and make good use of multi-dimensional keys that encrypted system of optical transform possess.Also,this method highlight advantage of hybrid system speed.

A new method of making three-dimensional hologram is presented.On the basic principle of two-step rainbow holography,we obtain the Fraunhoer phase information of three-dimensional object by digital coding the wave front of multi visual angle images.Such images are divided into small blocks and coding individually.In the experiments,the phase information of blocks was inputted into phase only liquid crystal on silicon spatial light modulator,the voxel image was reconstructed at the focal plane of fourier lens with laser ilumination and recoded with interference on photoresists.The whole three-dimensional image was obtained by matrix stitching voxel images.The results proved this mehtod.It will be an important technology of three-dimensional display.

Inverse Synthetic Aperture Imaging LADAR can realize the instantaneous high-resolution imaging for moving target. Howerver, the ultra-wide bandwidth of the laser signal and the weakness of the echo signal brings some difficulties in the signal sampling. A method which combines the optical heterodyne detection technique and compressed sensing theory is proposed to solve this problem. The optical heterodyne detection technique is utilized to reduce the bandwidth of echo signal, then the compressed sensing theory is developed to realize sampling and reconstruction of the signal. Simulations demonstrate that high-quality images can be reconstructed even though the sampling rate is much lower than the Nyquist rate.

Aiming at the IR 3D target recognition question, a method based on fast skeleton extraction is proposed.Based on the topology structure of target reflected by the skeleton, the correspondence between different targets′ structural portions are established. Within the corresponding curve segments, curves are matched based on curve alignment, and the similarity is evaluated according to the sum of all the segments′ cost. This method performs well in the present of commonly occurring visual transformations. Moreover, incorrect correspondence introduced by curve match′s drawback, that is, curve matching tends to match local parts, and ignores the global view of how these parts are spatial arranged with respect to each other, can be avoided. Experimental results show that this algorithm has a rather good effect on 3D target recognition.

By analyzing the characteristics of the HD measure,a real-time two-level scene matching algorithm is proposed.Compared with traditional image multi-scale feature decomposition matching methods,the proposed method is performed directly on the original resolution image and shortens the matching time by reducing both the number of match points and the computation complexity of similarity measure.The pixel-jump method decreases the participated match points greatly,and the computation of LTS-HD at each point is performed between sets consisted of only feature points,which efficiently simplify the computation of similarity measure.To ensure the match precision,a coarse-to-fine two-level matching strategy is adopted.In the first level,a coarse match point is obtained using pixel-jump searching through the reference image.In the second level,a point-by-point local searching is performed to get the accurate match point within the δ-neighborhood around the coarse point.Simulation results show that the proposed matching method takes less time than both the point-by-point searching and the genetic algorithm,and that the match point is correct even though the actual image is occluded severely.

In order to improve the target identification, Markov random field (MRF) is introduced in the target fusion process to build prior probability model of a class. Then aiming at selecting model parameter β, an EM-MAP-HMRF feature-level fusion algorithm is proposed based on non-homogeneous class and direction. HMRF is divided into centric and distributed-based fusion schemes. The simulations show that the two new fusion algorithms can improve the classification accuracy, and enhance the ability to anti-interference. However, they have different advantages. The two new schemes can be used in various fusion systems for different applications and improve the effectiveness of detection and identification for specific targets.

Utilizing the shape characteristics of object in multi-slits autocollimator and imaging characteristics of photo-electronic detector,the pixel edge of image filtered by gauss filter is detected by the algorithm which can be used to detect the edge of image.Based on it,local Newton interpolation functions are used to detect the sub-pixel edge of image.Furthermore,least square beeline edge fitting is used to improve detecting precision of the sub-pixel edges of image.After testing,0.13 arc second precision is achieved by the algorithm.

Based on Fourier-Bessel transformation, diffraction field distribution of Gaussian beam limited by the circular grating is calculated and analyzed. Compared with plane wave,the results show that, if the circular grating radius is 1.5 times of the incident light spot radius, with number of rings increasing, the variation of FWHM decreasing first and then increasing, power ratio of the central spot decreasing, the intensity of central principal maximum decreasing,which are accordance with these of plane wave. But the variation of central spots radius and secondary maximum intensity are different with these of plane wave.If number of rings is less than 5, diffraction field distribution of Gaussian beam limited by the circular grating change irregular. If number of rings is more than 10,diffraction field distribution change unobvious. If number of rings tends to infinite,the central spots radius, FWHM and secondary maximum intensity tend to these of Gaussian beam diffraction limited by circular aperture, power ratio of the central spot is equal to 1/2 of that Gaussian beam diffraction limited by circular aperture, and central Maximum light intensity is equivalent to 1/4 of that of Gaussian beam diffraction limited by circular aperture.

A new method of optical control is put forward based on conical effect in biaxial crystal.When the incident light spread along optical axis direction,the propagation direction will change with the polarization direction.By controlling the magnetic field on the magneto-optic modulator,the polarization direction can be changed,thus the laser beam direction control is realized.The fundamental of disk tracking is analyzed and overall plan is also designed,the relationship between polarizing angle and tracking displacement is obtained by numerical simulations,so this plan is reasonable.Compared with traditional tracking means of machine -electricity,this kind of plan has the following advantages:light weight,small volume and fast transient response.A new method for optical switch and scanning is provided meanwhile.

The equilibrium structure and single-point energy scanning of the ground state X2П and the excited states a4П and B2П of NO molecule are calculated using the CASSCF/MRCI method and the cc-pVDZ basis set. The potential energy curves are obtained by a least square fitting to the modified Murrell-Sorbie function. Employing the Rydberg-Klein-Rees method, the harmonic frequency and other spectroscopic data (αe 、ωe、 ωeχe、 βe ) of the ground state X2П and the excited states a4П and B2П of NO molecule are calculated and the calculation results are in better agreement with the experimental ones than other theoretical data. In addition, the eigenvalues of vibrational levels are calculated by solving the radial one-dimensional Schrdinger equation based on the analytical potential energy function.

In order to measure the stray light,which is one of the important influence factors in spectral accuracy,the definition, source and harmfulness of stray light are introduced. Cut-off filter method, spectrum method, spectral stray light factors method and so on are presented to discuss the advantages and disadvantages of normally used stray light measurement methods. Then, the feasibility and superiority of the stray light factor used to describe the stray light characteristics of the spectral instruments, is investigated. At last, the system components, measurement procedure and measurement results of the stray light measurement system, using narrow-band filter, are introduced, and the uncertainty of the results is analysed. Results show that the stray light factor indicates the stray light characteristics of the spectral instruments effectively without relationship to the light source, detector and other measurement conditions. The relative uncertainty of the measurement is 0.646% when the fiducial probability is about 95%, which can meet the needs of the stray light measurement.

Real-time monitoring the gelatinization process of single rice starch particle using laser tweezers Raman spectroscopy system under the condition of excessive water and special heating mode is reported. These Raman spectra of gelatinization process are acquired using an imaging CCD spectrograph and the gelatinization process is remarked by the changes of spectra peak height. The experimental result further confirmed the fact that the band of 477cm－1 is assigned as skeletal mode. The rate of gelatinization about single rice starch granules is studied by analyzing the C-O-H group related characteristic peaks which locate at the band of 1 052, 1 083, 1 127, 1 339 cm－1. The results demonstrate that the rate of gelatinization accelerates with rising temperature until the end of gelatinization process.

The basic pattern recognition theory of artificial neural network is introduced.The identification system for the oil′s three-dimensional fluorescence spectra is established based on the principal component analysis (PCA) and BP neural network method,and the system design and the basic frame of model are made.PCA was inducted to pre-analyze the feature parameters of oil′s three-dimensional, the principal components of original variables were used as the input of network, then the network output realized the identification of oil′s three-dimensional fluorescence spectrum. This method can cut down the dimensions of original input,eliminate the relativity between variables,at the same time simplify the network structure,and improve the convergence speed.Actual instance was tested effectively that the PCA-BP neural network compared with the normal neural network reduced training time and possesses better performance. Results showed that the method can be used to realize the identification of oil's three-dimensional fluorescence spectrum.

The optical configurations of off-axis spherical lens and off-axis correcting lens imaging spectrometer are designed. Based on the optical system of off-axis spherical lens imaging spectrometer, the spectrometer with off-axis lens is designed. This system adopts an off-axis lens in order to adjust large field aberration and avoids large diameter concentric lens. One prism corrects nonlinear dispersion and meets the request of spectral resolution. Distortion is controlled through adjusting off-axis angle and mirrors′ focus, which compensate spectral curve and decrease residual aberration. It is easy to reduce production difficulty. The characteristic of two systems is discussed from the aspects of engineering layout, production difficulty and image quality. And the result of spectral nonlinear and slit curve is shown. The minimum modulated transfer of off-axis spherical lens system is 75 percent better than the value 60 percent of off-axis correcting lens. The front system uses a silica lens which diameter is larger than 200 mm. The material uniformity and surface precision of the latter system is far better than the front system, and the production difficulty is decreased. The latter system considers the matching with mechanical structure, and it is more feasible for the distance between slit and the first mirror of latter system. The spectral resolution of front system is close to the latter, and the slit curve of the front system is slightly better than the latter system. The comparison shows that the latter is optimal optical layout, and it can be applied to remote sensing working at short wavelength.

The Raman multi-channels lidar developed by Wuhan University is described.The design principles of the whole system and main technical parameters are provided.The methods for retrieving aerosols’ optical properties such as atmospheric aerosol extinction coefficient,backscattering coefficient and lidar ratio are presented in detail,and the key part of retrieving the aerosol extinction coefficient is discussed and analyzed.The real-time detections of optical properties for aerosol,cloud and boundary layer in the low-altitude atmosphere are done.The experiments show that the multi-channels Raman lidar system has good performance for detecting the vertical distribution of aerosols in the night and it is reliable.