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Near-field holography (NFH), with its virtues of precise critical dimensions and high throughput, has a great potential for the realization of soft x-ray diffraction gratings. We show that NFH with reflections reduced by the integration of antireflective coatings (ARCs) simplifies the NFH process relative to that of setups using refractive index liquids. Based on the proposed NFH with ARCs, gold-coated laminar gratings were fabricated using NFH and subsequent ion beam etching. The efficiency angular spectrum shows that the stray light of the gratings is reduced one level of magnitude by the suppression of interface reflections during NFH.

A new and simple method is demonstrated to achieve size controllable nanochannels by using nanoimprint lithography and low-pressure thermal bonding methods. The flexible free-standing SU-8 allows the bonding of the nanochannels' pattern features at such a low pressure primarily because of ‘sequential’ bonding made possible by the bonding layer flexibility and the conformal contact made between the bonding layer and the structure layer in a large area. The simple geometrical argument shows that the height of the enclosed nanochannel can be determined by the depth of the cross-linked SU-8 trenches as well as by the initial thickness of the thin unexposed SU-8 layer. The height of the nanochannels can also be controlled by adjusting the ratio of the ridge width to the trench width on the SU-8 trenches. These simple relationships can serve as a guideline in choosing the parameters for SU-8 nanochannel fabrication.

Soft x-ray varied line spacing grating (VLSG), which is a vital optical element for laser plasma diagnosis and spectrometry analysis, is conventionally fabricated by holographic lithography or mechanical ruling. In order to overcome the issues of the above fabrication methods, a method based on electron beam lithography-near field lithography (EBL-NFH) is proposed to make good use of the flexibility of EBL and the high throughput of NFH. In this paper, we showed a newly designed soft x-ray VLSG with a central groove density of 3600 lines/mm, which is to be realized based on EBL-NFH. First, the optimization of the spatial distribution of line density and groove profile of the VLSG was shown. As an important element in NFH, a fused silica mask plays a key role during NFH in order to obtain a required line density of VLSG. Therefore, second, the transfer relationship of spatial distribution of line densities between fused silica mask and resist grating was investigated in different exposure modes during NFH. We proposed a formulation about the transfer of line density to design of the groove density distribution of a fused silica grating mask. Finally, the spatial distribution of line densities between the fused silica mask, which is to be fabrication by using EBL, was demonstrated.

With the development of micro- & nanofabrication technology, micro- & nanostructures have been widely used in many fields, including spectroscopy, coding, sensor, subwavelength element, etc. With phase masks realized by a combination of electron beam lithography (EBL), near field lithography (NFH) has great potential to fabricate versatile nanostructures, because it combines the advantages of both lithographic methods. Currently, subwavelength structures attract much attention due to their various functions, such as antireflection, polarization beam splitter and filter. In this presentation, aiming at reducing the interface reflection of a fused silica mask of NFH at a wavelength of 441.6 nm and incidence angles of either 0° or 32°. First, we will compare the difference of antireflection property of one-dimensional (1D) and two-dimensional (2D) subwavelength structures with line density of 3600 lines/mm by simulation. Then, the optimized 1D and 2D subwavelength structures with 3600 lines/mm will be fabricated by using EBL-NFH method. Finally, the antireflection property of these 1D and 2D subwavelength structures will be characterized at the wavelength of 441.6 nm.

Structure effects of distributed feedback (DFB) gratings on lasing action have been investigated for detecting explosive vapors. For the first time, we have established the optimized profiles of the DFB grating, and given the theoretical path to design its structure for amplified spontaneous emission (ASE) of organic polymer films based on Bragg conditions. A poly(p-phenylene ethynylene) (PPE) film can realize detection of dinitrotoluene (DNT) vapors in 2 min with a reduced excitation threshold of 26 mJ cm(-2) by using a simple and common 405 nm laser.

Patterned ferromagnetic thin film shows promising applications in ultra-high density magnetic storage, magnetoresistive transducer, magnetic random access memory and many other devices. Since the performance of these devices is closely associated with the magnetic properties of the etched patterns, it is necessary to study the effects of freshly etched surface oxidation on the magnetic properties of the patterned microstructures. In the current work, were carried out an X-ray Magnetic Circular Dichroism (XMCD) study on a 50 nm Co0.9Fe0.1 continuous thin film and a related patterned Co0.9Fe0.1 grating structure etched with a 2 μm period. Based on the sum rules, the spin and orbital moments were calculated for these two samples, respectively. The results indicated that the spin and orbital moments of grating structure (1.34µB and 0.24µB, respectively) decreased 17.3% compared with the corresponding continuous film (1.62µB and 0.29µB, respectively). We proposed that the moment decreasing of the patterned grating structure was mainly caused by the etched surface oxidation during the pattern manufacture process. The oxidation ratio of Co element in the patterned grating structure is 14.4% calculated from X-ray absorption spectroscopy (XAS) measurement. Considering the oxidation ratio, we amend the spin and orbital moment of Co and the amended result is basically in accordance with that of continuous film, demonstrating that the difference of the spin and orbital moments between the sub-micron grating unit and the continuous film is really caused by the oxidation.

In this paper, we demonstrate a new method for fabrication centimetre-long, dense and vertical sidewalls silicon-on-insulator (SOI) mould using holographic method combine with crystallographic anisotropic etching. Holographic method can make narrow dense and multiple continuous lines in large area while crystallographic anisotropic etching could eliminate line-edge-roughness (LER) in sidewalls and make the sidewalls nearly atomic-scale smoothness. Therefore, the line width of the SOI mould will in a high uniformity and the sidewalls will be smooth and vertical over centimetre lengths. Compare to common NIL mould, the smooth and vertical sidewall of SOI mould provided an easier demoulding process after NIL. Multiple centimetre-long fluidic-channels with smooth and vertical sidewall fabricated by faithfully imprint of SU-8 and an optimised sealing process using free-standing SU-8 bonding film.

Fluorinated reduced graphene oxide (F-RGO) is prepared by CF4 plasma treatment of RGO. The fluorine (F) doping is confirmed by X-ray photoelectron spectroscopy and its content is directly related to the plasma exposure time. A modest p-doping effect of the fluorination is observed from the electrical measurements. It is found that the F-RGO is an even better substrate for surface enhanced Raman spectroscopy of molecules than RGO. The relative enhancement factor can be tuned by manipulating the F content in the F-RGO. The effect is attributed to the presence of the strong local electric field induced by the local dipoles of F-containing groups on the F-RGO surface. This shows that the formation of well-designed surface dipoles could be a general way to increase the chemical enhancement of molecular Raman spectra.

This paper reports a novel method for the fabrication of silver electrode with high resolution using transfer printing method. The resolution can reach to 30@mm with high electrical conductivity as we keep a large depth and micro-size particles of the silver. In the study, we prepare the mixture binder for silver paste to improve the property of transferring. The parameters of the transfer process, including paste properties, pressure and surface energy, are also studied. Silver fingers of 50@mm width and 20@mm depth has been successfully fabricated on polysilicon and fired at 600^oC in Tube Furnace. The electrical conductivity after firing test is larger than 10^4S/cm. In this study, room temperature through the whole process and low pressure during the transferring will keep a low cost.

The soft X-ray interferometry is completed by the Mach-Zehnder interferometer using a soft X-ray laser, and it is also an important method to measure the electron densities of a laser-produced plasma near the critical surface. It is apparently demonstrated in this paper that the incident angle of each optical element in the soft X-ray Mach-Zehnder interferometer should be near normal incidence based on the polarized characteristics of the soft X-ray multilayers, and the product of reflectivity and transmission of the beam splitter should be taken as a standard of design according to the structure of the soft X-ray Mach-Zehnder interferometer. The beam splitters used in the soft X-ray interferometry at 13.9 nm are fabricated using the ion beam sputtering. The figure error of the beam splitter has reached the nanometer magnitude, in which the product of reflectivity and transmission of the beam splitter is more than 1.6%.

The basic principle and method to generate structural color from the photoresist grating of the multilayer dielectric diffraction grating are introduced. Rigorous coupled-wave analysis is used for computation with the open software RCWA-1D. The relationships between the characteristics of the photoresist and the structural color are explained. This paper discusses the effect of light source characteristics on the duty cycle color resolution, indicating that TE polarization is better than TM polarization, and the FWHM should be sufficiently large with an optimized value for the incident angle.

Fabrication-induced metal contaminations and subsurface damage are generally identified as the laser damage initiators that are responsible for the laser induced damage in fused silica. In this paper, the removal of those two initiators are realized by two methods: wet chemical surface cleaning and optimized HF-based etch process. Two kinds of chemical leaching are used to removing the Ce and other metal impurities respectively. In order prevent the redeposition of the reactive byproducts during HF etch process, we optimized the traditional HF etch process in two ways: absence of NH 4 F in etch solution and presence of megasonic and ultrasonic agitation during and after etch respectively. And laser damage tests show that these two treatments greatly improve the laser damage resistance of fused silica.

As a new type of grating, the freestanding blazed transmission grating combines the advantages of traditional transmission gratings (low mass, relaxed alignment and flatness figure insensitivity) with those of reflection gratings (high broadband diffraction efficiency, high spectral resolution). A freestanding blazed transmission grating with period of 1μm was successfully fabricated by holographic lithography and anisotropic wet etching of silicon. The duty cycle is about 0.13. The aspect ratio of a single grating bar is about 77. The thickness is 10μm and the open area fraction is about 58.8%. The size of a single die is 15mm×15mm divided into four 5mm ×5mm windows. The diffraction efficiency of the grating was measured at the National Synchrotron Radiation Laboratory in the wavelength region of 5-50nm. The results show a strong blazing effect in the direction of specular reflection from mirror-like grating sidewalls, as expected.

As an important optical element, beam sampling grating (BSG) is used in the terminal of inertial confinement fusion (ICF) drivers. It can provide a very slight sampling beam for the precision diagnosing of laser energy and wavefront distortion. However, in practice, its non-uniform diffraction efficiency seriously influences the accurate signal of sampling beam, and finally affects diagnostic ability. BSG is usually fabricated by holographic ion beam etched (HIBE) process. In this paper, a mechanical polishing processing technology was used to improve uniformity of the diffraction efficiency of BSG after HIBE. In the processing, cerium oxide (CeO 2 ) was used to polish the local areas of grating where exhibit higher diffraction efficiency with the purpose of changing the depth of grating profile, and then they have similar efficiency with the surrounding areas. By iteration of the above process, BSG finally achieve the improved uniformity of diffraction efficiency over the area of a 430 x 430 mm 2 . The RMS of diffraction efficiency of BSG after mechanical polishing shows great reduction down to 4.8% as compared with that of the as-polished RMS of 21%. The effects of this processing on laser damage was characterized by the measuring the LIDT for the laser radiations of 355nm.

A broadband [SiC/W/Ir](2) multilayer coating was deposited onto a diffraction grating to enhance the grating efficiency in the 50-100 nm wavelength range in a Seya-Namioka mount. The holographic ion-beam etched grating had a laminar profile with 1200 lines/mm. The coating was designed by using the subquarterwave multilayer theory. The measurement results show that the efficiency in the -1st diffraction order is greater than 9.3% throughout the wavelength range of 50-100 nm, which is obviously higher than that of single-layer gratings with SiC, Ir, or Au coatings.

In this paper, we present a novel method for the fabrication of high density pattern in PET foils employing nanoimprint lithorgraphy. The temperature and pressure dependence on the imprinted pattern were investigated. Well resolved PET nanopatterns (sub-100nm resolution) were transferred successfully. It is observed that the grating with different trench depths will demonstrates corresponding changes of diffraction intensity distribution. The grating imprinted in PET foils could broader applications in the manufacture of nanophotonic structures owing to its excellent flexibility and transparency. Based on the optimized imprint process, a novel method for the fabrication of phase gratings and nanochannels is presented. This developed process can find broader applications in the manufacture of nanofluidic channels and other nanophotonic structures.

Contaminants are deemed to be the initial source of optical-damage mechanisms as well as the main reason to decrease the Laser Induced Damage Threshold (LIDT) of multilayer dielectric pulse compressor gratings (PCG). In this paper, the Piranha solution was used effectively and nondestructively to remove the residual contaminants on the surface of PCG. The surface cleanliness was evaluated by Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). The higher removal efficiency was achieved with more times of multiple-cleaning by fresh Piranha solution which has an effectiveness for a given period of time.

A simple and new system for measuring the diffraction efficiency of large aperture gratings at littrow angle is established in this paper. The reference grating Po, double beams and timer with shutter have been draw into the system for eliminating the impact of polarization and stray light, fluctuation of incident light, and the fatigue of photodetector. A program is designed to scan, measure and calculate the diffraction efficiency of the gratings automatically. The diffraction efficiency accuracy measured for the gratings is increased by ~1% with this system. To achieve more measured accuracy, additional beam of reflection light should be imported.

In this paper, we describe a new fabrication process utilizing polydimethylesiloxane (PDMS) and polyester (PET) as a sacrificial substrate for fabricating free-standing SU-8-based nanofluidic system. The soft substrate permits SU-8 UV cured patterning and layer-to-layer bonding, and allows the SU-8 structures to be easily peeled off from the substrate after complete fabrication. In the process, PDMS-on glass is used as a handling wafer, on which SU-8 based trenches is imprinted by a flexible film mold using low-pressure nanoimprint lithography. The reservoir pattern of SU-8 is fabricated on the bonding layer, in which PET serves as substrate. The nanochannel is sealed by optimized bonding process, which is flexible and easily controllable with the use of soft substrate as a sacrificial layer. After bonding process, PDMS and PET could be easily peeled off from nanaofluidic system. The SEM results shows that the height of the fully enclosed nanochannels will be about hundreds nanometer. Large area of free standing SU-8 structure layers are successfully fabricated and peeled off from the soft substrate layer as single continuous sheets.

The rigorous coupled-wave method (RCWM) is extended to calculate the diffraction efficiency of multilayer grating in spectrum with strong absorption. This paper gives a detailed algorithm analysis of the RCWM, an enhanced, numerically stable transmittance matrix approach applied to homogenous layered media is generalized for multilayer grating structure. In order to calculate in the lossy medium, the wave vector of electric field is redefined. This method is programmed to design multilayer grating which is expected to use on Seya-Namioka synchrotron monochromator in vacuum ultraviolet (VUV) spectrum. The influence on diffraction efficiency caused by grating profile and multilayer stack is analyzed theoretically. The diffraction efficiencies of well-designed multilayer gratings are all greater than 10% in 50-110nm region, and they are about two to three times higher than that of the single metallic layer grating which is being used on Seya-Namioka monochromator now.

INNOSLAB lasers are characterized by: short pulse length and high peak power, high pulse repetition rate, high beam quality and flexibility in beam profile, from circular beam profile, through line shaped one dimensional Top-hat, to two dimensional top-hat with rectangular or square cross section. Their tailor able beam profiles open for INNOSLAB laser a variety of applications with high energy efficiency, such as glass milling, parallel scribing, high throughput ablation, particle imaging velocimetry and pumping of dye lasers.

Through an optimal combination of crystal shape, cooling and resonator design, InnoSlab lasers possess unified advantageous features of short pulse duration and high peak output power, high pulse repetition rate, high beam quality and high flexibility in beam profile, from circular beam profile, through line shaped one dimensional Top-hat, to two dimensional Top-hat with rectangular cross section. We report diode end pumped, electrooptically q-switched Nd:YLF, Nd:YAG and Nd:YVO4 slab laser and their efficient harmonic generation in near field. Using oscillator/amplifier with Nd:YAG slabs over 50mJ pulse energy at 6kHz was obtained. The pulse length is 7ns and the peak power is as high as 7MW. With Nd:YVO4 slabs 400W average power at 50kHz was obtained. The pulse length is as short as 8ns. Because of the high peak power over 300W second harmonic is achieved by two LBO crystals.

We demonstrate a novel method for fabricating glass microlens (arrays) with single step on conventional lens surface. In this method, the glass microlens can be achieved by only one step with sol gel glass material. The microlens aperture and focus length can be controlled easily and uniformly. The fabricated sample shows good focusing property. This work will be useful to improve the performance of compound eyes optical system such as camera, telescope, 3D integral imaging and so on.

We demonstrate a method of fabricating varied-line-spacing grating by employing elastic medium with variable vertical section. The advantages of this technique include continuous variation of line spacing, high fabrication efficiency, low cost, etc. It is very difficult or impractical to produce this variation of line spacing by traditional interference lithography. This kind of grating can be used in an optical position sensor to improve the precision of the sensor.

Through an optimal combination of crystal shape, cooling and resonator design, INNOSLAB lasers possess special features: short pulse duration and high peak output power, high pulse repetition rate, high beam quality at high average power and flexibility in beam profile, from circular beam profile, through line shaped one dimensional top- hat, to two dimensional top-hat with rectangular cross section. Those open for INNOSLAB laser a variety of unique applications with added value, such glass processing, scribing, and particle imaging velocimetry and pumping of dye lasers.Through an optimal combination of crystal shape, cooling and resonator design, INNOSLAB lasers possess special features: short pulse duration and high peak output power, high pulse repetition rate, high beam quality at high average power and flexibility in beam profile, from circular beam profile, through line shaped one dimensional top- hat, to two dimensional top-hat with rectangular cross section. Those open for INNOSLAB laser a variety of unique applications with added value, such glass processing, scribing, and particle imaging velocimetry and pumping of dye lasers.

UV curing nanoimprint is demonstrated for high aspect ratio gratings fabrication based on SU-8 for nanophotonics and biochemical applications. The defects, which are caused by stress and friction between mold and resist and air bubbles are key issues. To eliminate the defects, the process parameters, such as imprinting pressure, baking time and demolding temperature, are optimized. SU-8 grating with 150nm in width and 1.5µm is presented with good uniformity in large area using Si template fabricated by non-switching DRIE process. The process could find broader applications in the manufacture of biochemical devices and nanophotonic structures.

We present new progress of the diffraction grating interferometer being pre-aligned used a double frequency grating. To measure the parallelism of the double frequency grating to a nicety before being built in the interferometer, a device based on Diffraction Technique for measuring the parallelism of the double frequency grating is designed. It is built of a semiconductor laser, a collimator, gratings, a precision turnplate, a beeline workbench, a redressal shelves, a ccd detector. The system error of the device is analyzed in this paper, and the parallelism of the double frequency grating is measured by this device. The results demonstrate that the diffraction measuring device suits the parallelism measured the diffracting grating interferometer based on the double frequency grating of that parallelism can attain a high pre-aligning precision.

Magnetic submicron meter structures were fabricated on Co 0.9 Fe 0.1 films by laser interference lithography combined with ion beam etching. The vertical standing wave was restrained by using proper exposure dose and appropriate development time. Hysteresis loops of the magnetic film and magnetic patterns were presented by surface magneto-optical Kerr effect. The difference magnetism between magnetic patterns with different critical sizes and the film was discussed.

A binary transmission phase grating is designed to operate as a dispersive element used in soft x-ray plasma diagnostic in ICF (inertial confinement fusion). The first and zero orders diffraction efficiency is simulated as a function of wave length and grating thickness. It is shown that the first order diffraction efficiency of a transmission phase grating can be up to 23.3% of the incident light, whereas that is not more than 10% for a conventional amplitude transmission grating. The transmission phase grating is fabricated in gold film supported by polyimide membranes using holography and ion beam etching method. The primary experimental results are presented.

Parameters of two spherical waves are firstly optimized to get the exact groove densities of diffractive gratings. Consequently, the groove density differences between on the plane and on the curved substrates are derived. Therefore, some experimental results are provided to demonstrate the validity of this method above. Meanwhile, the curvatures of the substrates are measured three times by using long trace profiler (LTP), which assures the repeatability of the bending technique for grating substrates. At last, the advantage of this method is exhibited through comparing the errors of grating groove density fabricated by this technique with only two spherical waves.

As a chemically amplified resist, UVN30 has been evaluated for mask use in high density pattern rapid fabrication by electron beam lithography. This resist displays excellent sensitivity and reasonable resolution for dense features. At optimum conditions proximity effect is eliminated and 75 nm and 150 nm dense lines resolved in a 300 nm thick film with writing field of 1mm 2 . With UVN30 mask, Si nanostructures are etched by non-switch DRIE etch chemistry developed in this work, which achieves high etch rate and smooth sidewall. This method is a promising technique for fast speed fabrication of nanophotonics, nanochannels and Si master stamps for nanoimprint.

The major etching processes of a large-aperture multilayer diffraction grating, including the uniformity of the ion beam current along the major axis and the on-line measurement of the diffraction intensity distribution are described. A large-aperture ion beam etcher with radio frequency linear source has been developed to fabricate large-aperture diffractive optical elements. The length with ±5.1% uniformity of the ion beam current distribution along the major axis is 30 cm. A series of multilayer diffraction gratings were etched successfully by using this etcher with CHF 3 chemistry. Multilayer diffraction gratings on a 80 mm×150 mm BK7 substrate etched for laser systems are shown. The grating exhibits an averaged diffraction efficiency about 96% at TE polarization of 1 064 nm light viewed at Littrow angle.

In recent years, a new fiber position sensor based on wavelength encoding plane variable-line-space gratings is developed and has attracted more and more interest. In this paper the theoretical background to the fiber position sensor concept is briefly described. The large slope groove density distribution variable-line-space grating with holographic recording is used in fiber position sensor. The preliminary results obtained were quite noteworthy. Due to the unevenness of the incident light intensity in different wavelength, the diffractive intensity of different position change quickly. The diffraction wavelength curve of the system is given. The resolution of the position sensor is also discussed in this paper.

The short wavelength, high brightness and good spatial coherence of soft x-ray lasers make them ideal sources for the diagnostics of dense plasmas. As a widely used diagnosing tool in the research of laser-produced plasma, interferometry has many advantages in the accurate measurement of the plasma electron density because it directly gives refraction index mapping from the interference pattern processing. The electron density gradient and electron density of larger variety plasma will be probed by the soft X-ray diffraction grating Mach-Zehnder interferometer (DGI). At the wavelength 13.9nm which our DGI uses, we fabricate a laminar grating used as the splitter grating. Its groove density is 1000g/mm, groove depth is 13nm, duty cycle is 0.4±10%. The zero and first diffracted order beams have an equal metrical diffraction efficiency about 25 percent at 81.3 degrees, and the maximum of the product is 7.6 percent at 81.2 degrees. The results illustrate the laminar grating is suitable for being used as a new pattern splitter grating at the wavelength 13.9nm.

It is known that rectangular grooves profile and various duty cycles (line to pitch) are required to attain maximum efficiency. The gold transmission phase gratings have been fabricated using holography and ion-beam etching techniques. The latent image monitoring technique and real time end-point detection technique were utilized to improve control of the shape of grooves and duty cycle during exposure and development, respectively. It is difficult to produce gratings with larger duty cycle in photoresist on gold for standing wave, nevertheless it is revealed in our work that the duty cycle can be more than 0.4 for the case for photoresist on gold substrates if development is stopped where the slope of the monitoring curve begins to drop off, not at the peak of the diffracted signal. In ion-beam milling, the influence of redeposition on the shape of grooves and duty cycle has been overcome by using a thin mask of Chromium with a comparatively low ion-etch rate and tilting and rotating substrates beneath the ion beam. Finally, some gold phase gratings with the duty cycles in the range of 0.25-0.45 have been obtained, whose duty cycle value is about 0.45, and their grooves profile is trapezoidal profile whose left and right facets are both more than 83 degrees approximately.

A novel process that combines interference lithography and ion beam etching is presented for fabrication of magnetic submicron structures and nanostructures in this paper. Instead of an antireflective coating, vertical standing wave patterns were removed using oxygen descumming process. A series of magnetic submicronmeter structures were fabricated on Co 0.9 Fe 0.1 films by this technique. Fabrication of magnetic nanostructures was performed by using a high exposure dose and modifications in optimized development c onditions. A thin Au film was deposited on the sidewall of the magnetic nanostructures to avoid the oxidation of Co and Fe. The effect of this method was confirmed by X-ray photoelectron spectroscopy (XPS). Hysteresis loops measured by a highly sensitive superconducting quantum interference device (SQUID) technique show the different magnetic properties of the magnetic patterns with different critical dimensions. Keywords: holographic lithography, patterned media, oxygen descumming, hysteresis loops

We present results on the nanofabrication of high density patterns in SU-8 resist, based on nanoimprinting combined with UV curing. The bilayer process using PMMA as sacrificial layer was developed to release the SU-8 layer to form three dimensional structures. The SU-8 displays excellent imprint property and well defined patterns are achieved at at low temperature, low pressure after demolding process. Using this technology, 300nm period SU-8 subwavelengh gratings and nanochannels were fabricated on flat substrate with good fidelity. This sacrificial layer-assisted UV curing imprint technology offers versatility and flexibility to stack polymer layers and sealed fluidic channels.

Beam sampling gratings (BSGs) employed in high-power laser systems usually have large aperture so that the adequate uniformity of diffraction efficiency is difficult to obtain. We proposed a deterministic method using controllable non-uniform etch to improve the efficiency uniformity of large-aperture BSGs. During the ion beam etching (IBE) process, etch depths are finely adjusted by the dynamic leaf. The motion trajectory of the dynamic leaf is calculated using the fine adjustment algorithm. Simulations are conducted on the basis of a typical example. The simulation predictions show that the cumulative error is 0.067 nm and about 99.1% of depth differences are in the range of the required etch depth tolerance, which suggests that the diffraction efficiency uniformity of BSG is expected to be effectively improved and thus can meet the requirement of a RMS of 5%. As a cost-effective solution, it also has a broad prospect in many optical fabrication fields, especially for the fabrication of large optics.

Diffraction gratings are designed for grazing-incidence operation in the soft x-ray spectral region. The efficiencies for various diffraction orders are simulated as a function of angle of incidence and blazed angles. According to the beat phenomenon, the grating pattern with double-frequency on the same substrate is recorded in a holographic way. The blazed grating will be fabricated using holography and ion beam etching method. The primary experimental results are presented. This kind of blazed grating is a key element used as a beam splitter of soft x-ray Mach-Zehnder interferometer, which is a new tool to diagnose the plasma generated by the laser-based inertial confinement fusion.

In recent years, a new fiber optic position sensing technology with holographic variable line-space (VLS) plane grating is developed. The period of VLS plane grating is about less than 10 micron. The grooves of the holographic VLS plane grating are not straight in general. Due to the grooves bend of 2-D holographic VLS plane gratings, measurement errors of the position sensor are inevitable when the scanning direction of a position sensor isn't in the symmetry axis of a VLS plane grating. This work briefly describes the theoretical background to the position sensor concept and the geometry theory of holographic VLS gratings. We report a theoretical analysis of the measurement errors in two basic cases: translation deviation and rotation deviation. The proposed method has been applied to examples of computer simulation. The results obtained are quite noteworthy.

Variable Line-Space gratings play an important role in focusing and aberration-reduced. They are widely used in spatial spectrum and synchrotron radiation facilities. However the design and fabrication methods of them are difficult. The problem is to be able to record holographically the expected grooves distribution. The geometric theory of aspheric wave-front recording optics is briefly described. We introduce the genetic algorithm to the parameters optimization of holographic variable line-space gratings. In order to obtain a steady set of recording parameters, we propose that the objective function of the genetic algorithm should consider the effect of the recording parameters errors. The integral expression of the objective function is also derived to improve the efficiency of calculation. Design example of holographic variable line-space plane gratings for a position sensor is given to demonstrate the capability of this method. The line-profiles of variable line-space plane gratings with different recording parameters are also compared in this paper.

Ronchi gratings are widely used as beam splitters in interferometry. The phase Ronchi gratings are fabricated in K9 (or BK7) substrates using a photolithographic process and ion beam etching process. The geometry of the gratings was determined within the approximations of the scalar diffraction theory to minimize their diffraction intensities in 0 and 2 orders at 514.5nm. Their diffractive characteristics are measured using Ar+ laser at 514.5 and 496.5nm. The phase Ronchi gratings exhibit the diffraction intensity in 0 or 2 order to be three orders of magnitude less than that in 1 order. Soft x-ray condenser zone plates are one of the most essential condensing and dispersing elements in the field of soft x-ray microscopy. The zone-plates are used at 3.2nm, whose diameters are 2.8mm. The widths of their outermost zone are 647nm. The zone plate is made of Au. Self-supporting zone plates are fabricated by holography-ion beam etching process to obtain x-ray lithography mask, the x-ray lithography, photolithography and micro electroplating process were used to obtain their self-supporting structure. The self-supporting zone plates are free of membrane absorption and degradation.

Holographic and ion beam etching technique has become routine means for fabricating vacuum ultraviolet and soft x-ray diffraction gratings. A novel technique has been successfully, in which oxygen reactive ions etching was used to achieve resist ashing of the grating, to fabricate diffraction gratings with holographic ion beam etching. The new technique was used to fabricate a spherical blazed grating, 1200g/mm and 130 nm blazed wavelength, and some laminar gratings for monochromators in the beamline of National Synchrotron Radiation Laboratory. The results show that the new technique can considerably lower the stringent requirements of holographic exposure and development, and makes it controllable to make smooth grooves with desirable depth and duty cycle. A gold transmission grating is one of the critical elements in the soft x-ray spectrometer for plasma diagnostics. With holographic-ion beam etching technique, a number of self-supporting transmission gratings have been fabricated for inertial confinement fusion (ICF) diagnosis.

Soft X-ray Microscopy station is one of the first constructed facilities at NSRL. The main instrument of the beamline is a monochromator which can provide the monochromized X-rays varying from 2.0 nm to 5.0 nm. Our holographic image employs the X-rays, so called “water window,” and experimental setup is arranged in a Gabor in-line way. Holograms are recorded on the photoresist polymethyl methacrylate (PMMA) and readout with ordinary light microscopes or atomic force microscopes (AFMs). They are reconstructed using optical or numerical methods. So far the holograms of some samples and their reconstructed images are acquired. Those samples include minute granules, cobweb and so on. The estimated resolution of the reconstructed images reaches the level of submicron. It is limited by the coherence of the X-rays used for these experiments. And it is possible to improve the resolution in the future.

With holographic-ion beam etching technique, a number of self-supporting transmission gratings have been fabricated for inertial confinement fusion diagnosis. In addition to the general process, a practical method for monitoring the evolution of the grating structures exposed in photoresist during development of the resist. The real-time monitor technique developed here is relatively simple in comparison with a He-Ne laser and detector, which needs delicate control.

In this paper a brief description is given to introduce the activities of the manufacturing technology using the synchrotron radiation light source in the National Synchrotron Radiation Laboratory (NSRL). The light source in NSRL is a dedicated synchrotron radiation facility in China. Five beamlines and corresponding experimental stations, including soft x-ray lithography, have been constructed. The main experimental results obtained from the soft x-ray lithography station are reported. We have fabricated some devices using the synchrotron radiation lithography, for example, the high electron mobility transistor, high T c superconductor infrared detector-array, diffraction grating, and micro condenser zone plate. A simple method for the achievement of synchrotron radiation x-ray lithography mask will also be presented. The LIGA (German abbreviation for: Lithograpie, Galvanoforming, and Abforming) technique has been developed in NSRL. It is the most promising technique for the fabrication of three-dimensional microstructures. We are successful in making several microdevices by deep x-ray lithography and microelectroforming, such as microgearwheel, micro acceleration sensor.

Laminar-type gratings as soft x-ray beam splitters for interferometry are presented. Gold-coated grating beam splitters with 1000 lines/mm are designed for grazing incidence operation at 13.9 nm. They are routinely fabricated using electron beam lithography and ion etching techniques. The laminar grating is measured to have almost equal absolute efficiencies of about 20% in the zeroth and -1st orders, which enables a fringe visibility up to 0.99 in the interferometer. The discrepancy of the grating profiles between the optimized theoretical and the experimental results is analyzed according to the comparison of the optimized simulation results and the measurement realization of the grating efficiencies. By a precise control of the grating profile, the grating efficiency in the -1st order and the fringe visibility could be improved to 25% and 1, respectively.

We reported on an all-solid-state double Nd:YAG slab laser. The laser was based on two diode end-pumped Nd:YAG slabs and a stable-unstable hybrid resonator. A cw output of 189 W and an average Q-switched output of 169 W at 10 kHz with an M(2) factor of 1.5 in the slow direction and 1.7 in the fast direction were obtained. We demonstrated efficient near-field frequency doubling by imaging the one-dimensional top-hat near-field to a lithium triborate frequency doubler. We obtained 93 W green light at 10 kHz with a pulse width of 10.7 ns. The efficiency of second-harmonic generation was up to 57%.

Grating beam splitters have been fabricated for soft X-ray Mach- Zehnder interferometer using holographic interference lithography. The grating beam splitter consists of two gratings, one works at X-ray laser wavelength of 13.9 nm with the spatial frequency of 1000 lines/mm as the operation grating, the other works at visible wavelength of 632.8 nm for pre-aligning the X-ray interferometer with the spatial frequency of 22 lines/mm as the pre-alignment grating. The two gratings lie vertically on the same substrate. The main feature of the beam splitter is the use of low-spatial- frequency beat grating of a holographic double frequency grating as the pre-alignment grating of the X-ray interferometer. The grating line parallelism between the two gratings can be judged by observing the diffraction patterns of the pre-alignment grating directly.

Varied-line-spacing gratings are used in soft-x-ray monochromators and spectrometers because of their ability to correct various aberrations by varying the groove density. A curved grating blank in a Rowland circle mounting could eliminate primary aberrations. Bending a plane constant-groove-density grating into a desirable surface can eliminate higher-order aberrations as a result of the change in surface profile and groove density. This provides a simple means for improving the imaging properties. When used in a monochromator, the grating can be bent to different degrees to minimize aberrations at all wavelengths. General formulas concerning the transformations of groove function, groove density, and groove spacing are presented for the bending grating. Analytic results with a numerical example show the significant properties of the system.