中国开放科研知识云: 检索

The characteristic performance of an extreme ultraviolet MCP-based photon-counting imaging detector 会议论文
5th International Symposium on Photoelectronic Detection and Imaging, ISPDI 2013, June 25, 2013 - June 27, 2013, Beijing, China
Ni Q.; Song K.

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Power scaling and beam divergence compression of bottom-emitting vertical-cavity surface-emitting lasers 会议论文
5th International Symposium on Photoelectronic Detection and Imaging, ISPDI 2013, June 25, 2013 - June 27, 2013, Beijing, China
作者: Zhang X.; Qin L.

收藏 | 浏览/下载：22/0 | 提交时间：2014/05/15

Immersed nanospheres super-lithography for the fabrication of sub-70nm nanoholes with period below 700nm (EI CONFERENCE) 会议论文
2012 12th IEEE International Conference on Nanotechnology, NANO 2012, August 20, 2012 - August 23, 2012, Birmingham, United kingdom
Li S.; Shi L.; Yang Z.; Huang X.; Zhang Z.; Gao F.; Guo Y.; Yu W.; Du J.

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A maskless nano-lithography method by using polystyrene spheres (PSs) self-assembled on silver slab (NSSL) was proposed in [optics express Vol. 16 No. 19 (2008) 14397]. Following that to break the limitations in resolution and PSs period of NSSL method in this paper we present PSs immersed super-resolution lithography (NSISL) technology by embedding the PSs into appropriate material to improve the efficiency of the surface plasmon excitation. The energy modulating mechanism and the rules of the resolution affected by silver slab were studied by calculating and analysing the energy distribution. The curve of the lithography resolution versus the silver thickness was presented. In order to verify this method contrast analysis was carried out with NSSL. The results show that the lithography resolution is improved efficiently. Taking a specific configuration with PS diameter of 600nm as an example the resolution was improved to 54nm from 190nm with Ag thickness of 25nm. Based on the calculation results we carried out the experiments. Nano holes with dimension of 75nm and period of 600nm were obtained. 2012 IEEE.

A composite hardness stamp in 184 PDMS for nanostructures transfer in high fidelity (EI CONFERENCE) 会议论文
2012 12th IEEE International Conference on Nanotechnology, NANO 2012, August 20, 2012 - August 23, 2012, Birmingham, United kingdom
Li S.; Shi L.; Yang Z.; Huang X.; Zhang Z.; Gao F.; Guo Y.; Yu W.; Du J.

收藏 | 浏览/下载：13/0 | 提交时间：2013/03/25

To improve the fidelity of nanostructures in transfer process a composite stamp with reasonable hardness distribution in 184 PDMS used to nanoimprint was studied. The stamp is composed of a stiff 184 PDMS structured layer and a soft 184 PDMS supporter layer. We studied the relationship between the hardness of the 184 PDMS and the proportion of each component in 184 PDMS. The appropriate components proportions of prepolymer and curing agent corresponding to the different region of the composite stamp were presented. The fabrication method of the stamp is also presented. Corresponding experiments were carried out by using this stamp. Kinds of nanostructures were transferred in one inch diameter area with good fidelity. The feature sizes of the structures were less than 100 nm. 2012 IEEE.

Far-field focusing of laser beam based on digital image processing techniques (EI CONFERENCE) 会议论文
Optoelectronic Imaging and Multimedia Technology, October 18, 2010 - October 20, 2010, Beijing, China
Zhang H.-Y.; Zhao S.; Guo J.; Liu L.-S.; Tian Y.-Z.

收藏 | 浏览/下载：20/0 | 提交时间：2013/03/25

In order to lead the laser beam transmit in the atmosphere convergently an experiment of laser focus at the distance of 450m and 300m has been operated in the outdoor place. The actual manipulations are as follows: Firstly the laser was collimated by a beam expander then the near-parallel laser beam was transmitted with a Galileo telescope system and the distance between the concave lens and the convex lens can be tuned through a precise displacement platform so the focus of the system changed due to the tiny displacement of the concave lens. Secondly the average power of the laser spot can be measured using power meter the power is 47.67mW and the standard deviation is 0.67mW while the focal length is 450m. Thirdly the energy distribution was found through the laser beam analyzer. The spot images were saved using the beam analyzer then the saved image can be processed with Matlab software afterwards. The function named EDGE and Sobel operator was used in the pre-processing of the saved image then method of median filter was used in the course of image de-noising and 53H filter was adopted in the signal analysis. The diameter of laser spot was obtained by the method above the diameter is 5.56mm and the standard deviation is 0.24mm. The spot center excursion is 0.56mm it is 10.43% of the total diameter of the laser spot. At last the key factors of the energy dissipation in the focusing system can be summarized as follows: restriction of the diffraction limit attenuation in the atmosphere geometrical aberration of optical system and the diffraction limit and the geometrical aberration are significant in the three factors above so we can reduce the impact of the both factors during the design of optical system. The reliable referenced data of the system design can be acquired through the primary experiment research. 2010 SPIE.

Dome design and coupled thermal-mechanical analysis of supersonic missile (EI CONFERENCE) 会议论文
2009 International Conference on Optical Instruments and Technology, OIT 2009, October 19, 2009 - October 22, 2009, Shanghai, China
Xing-qiao A.; Qun W.; Hong-guang J.

收藏 | 浏览/下载：39/0 | 提交时间：2013/03/25

A review of high-speed flow pressure and aerodynamic heating effect on Supersonic missile's dome is given. The dome should have excellent properties in optical mechanical and chemical characteristics. A design of dome on supersonic mode is described according to tactical guide line of a missile. The dome made of quartz which is about 8mm thick and 141mm in window diameter. To check up the reliability of the dome a reasonable finite element model (FEM) of dome is established and a thermal-mechanical Analysis to the dome by finite element software NASTRAN has carried on through these can obtained the distribution of temperature field and stress field when the speed is 2.3Ma. The results indicated that the stress was concentrated in the joint of the dome end and the Missile Section and the maximum stress was 16.4Mpa. The stress of other nodes was smaller than the allowable stress of quartz glass. Reference to the results of the analysis a lightweight revision to the dome structural dimension and a new method of dome fixing have put forward which can reduce the stress concentration. 2009 SPIE.

A novel bottom-emitting vcsel's one-dimension array (EI CONFERENCE) 会议论文
Optoelectronic Materials and Devices III, October 27, 2008 - October 30, 2008, Hangzhou, China
Cui J.; Ning Y.; Li T.; Zhang Y.; Liu G.; Zhang X.; Wang Z.; Shi J.; Kong P.; Qin L.; Liu Y.; Wang L.

收藏 | 浏览/下载：17/0 | 提交时间：2013/03/25

A novel 980nm bottom-emitting VCSELs array with high power density and good beam property of Gaussian far-field distribution is reported. This array is composed of 5 symmetrically-arranged elements of 200m 150m and 100m-diameter with the center spacings of 300m and 250m respectively. The maximum power is 880mW at a current of 4A corresponding to lKW/cm2 average optical power density. The differential resistance is 0.09 with a threshold of 0.56A. The novel array is compared with a 300m-aperture-size single device and a 44 2-D array with 50m element aperture size and 250m centre spacing. The three devices have the same lasing area. The conclusion is that the novel array is better in the property of output power threshold current lasing spectra far-field distribution etc. 2008 SPIE.

The synthesis and field emission property of carbon nanotubes on carbon fibers substrate (EI CONFERENCE) 会议论文
Technical Digest of the 20th International Vacuum Nanoelectronics Conference, IVNC 07, July 8, 2008 - July 12, 2008, Chicago, IL, United states
Leyong Z.; Weibiao W.; Jingqiu L.; Yuxue X.; Da L.; Song C.; Haifeng Z.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

Using ferrocene as catalyst precursor C2H2 as carbon source carbon nanotubes (CNTs) with uniform density were synthesized on carbon fibers substrate by floating catalyst method. The morphology and microstructure were characterized by field emission scanning electron microscope (FESEM) and high-resolution transmission electron microscopy (HRTEM). The observation showed that the length of CNTs is about 2 m the average space between adjacent CNTs is about 300 nm and the diameter of CNT is about 45 nm. The less dense "short and stubby" aligned CNTs films should have good electron field emission characteristics. The results of field emission showed that the emission current of CNTs/carbon fibers was 5 A at the field of 2.5 V/m and the emission current can be 280 A with a field of 7 V/m (the specimen area is 0.25 cm2 and the distance between cathode and anode is 200 m). The calculation based on the F-N plot indicated that the field enhancement factor of CNTs tip is 499122. Using the conductivity and chemical stability of carbon fibers and the uniform and sparse density distribution of CNTs on carbon fibers substrate the tip predominance of carbon nanotubes can be exerted and simultaneously the effect of screening effects between adjacent carbon nanotubes on the field emission performance can also be effectively decreased. The CNTs synthesized on carbon fibers substrate has many predominances for the fabrication of cold cathode devices. For example using the removability of carbon fibers the cathode of CNTs/carbon fibers can be arbitrarily moved enlaced or combined to form different patterns and the cathode of CNTs/carbon fibers can be also fabricated in large size. Therefore CNTs/carbon fibers may have potential application in field emission displays.

High power VCSEL device with periodic gain active region (EI CONFERENCE) 会议论文
Optoelectronic Materials and Devices II, November 2, 2007 - November 5, 2007, Wuhan, China
Ning Y. Q.; Qin L.; Sun Y. F.; Li T.; Cui J. J.; Peng B.; Liu G. Y.; Zhang Y.; Liu Y.; Wang L. J.; Cui D. F.; Xu Z. Y.

收藏 | 浏览/下载：20/0 | 提交时间：2013/03/25

High power vertical cavity surface emitting lasers with large aperture have been fabricated through improving passivation lateral oxidation and heat dissipation techniques. Different from conventional three quantum well structure a periodic gain active region with nine quantum wells was incorporated into the VCSEL structure with which high efficiency and high power operation were expected. The nine quantum wells were divided into three groups with each of them located at the antinodes of the cavity to enhance the coupling between the optical field and the gain region. Large aperture and bottom-emitting configuration was used to improve the beam quality and the heat dissipation. A maximum output power of 1.4W was demonstrated at CW operation for a 400m-diameter device. The lasing wavelength shifted to 995.5nm with a FWHM of 2nm at a current of 4.8A due to the internal heating and the absence of active water cooling. A ring-shape farfield pattern was induced by the non-homogeneous lateral current distribution in large diameter device. The light intensity at the center of the ring increased with increasing current. A symmetric round light spot at the center and single transverse mode operation with a divergence angle of 16 were observed with current beyond 4.8A.

Key techniques of laser direct writing of fine lines on the spherical surface (EI CONFERENCE) 会议论文
ICO20: Optical Design and Fabrication, August 21, 2005 - August 26, 2005, Changchun, China
Liang F.; Hu J.

收藏 | 浏览/下载：15/0 | 提交时间：2013/03/25

The main principles of laser direct writing (LDW) system for lines on the spherical surface (SS) are discussed. It is pointed out that line profile is determined by the exposure dose distribution which lies on the light intensity distribution of focus plane and the scanning speed. To improve the quality of line profile on the SS several key techniques as follows are introduced. Firstly the unique system configuration four axes mutually intersecting at the center of the SS is adopted which ensures the shape of the focus be maintained circular during the writing period. Secondly an automatic focus system (AFS) with the function of automatic focus in a certain range is introduced. Thirdly to guarantee the linear velocity to accord with the exposure character of the photoresist all the time an efficient arithmetic that controls motors run at appropriate angular velocity in different latitude is developed. Finally to achieve a stable and well-behaved system so as to compensate the velocity instability resulting from unavoidable errors of mechanical and electronics factor a powerful programmable multi-axis controller (PMAC) is utilized as the kernel element of the servocontrol system and the curves of step response and parabolic response achieved by feedforward and PID loop tuning indicate that the location precision and velocity stability have reached a high level. The experimental results of LDW of lines on the SS work piece with a diameter 30 mm and a radius equal to 100 mm are given. The section analysis of the lines on the photoresist by the atomic force microscope (AFM) after exposure and development is performed. The results show that line width is about 3.0 m and the steep sides of the lines are parallel to each other.

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