Record high extreme-ultraviolet efficiency at near-normal incidence from a multilayer-coated polymer-overcoated blazed ion-etched holographic grating

We have measured the extreme-ultraviolet (EUV) efficiency of a polymer-overcoated blazed ion-etched holographic test grating. The grating had a magnetron-sputtered Mo2C/Si multilayer coating matched to the grating blaze angle of 2.78 degrees. At an angle of incidence of 5.6 degrees and a wavelength of 15.79 nm, the measured efficiency peaks in the second outside order at 29.9%. The derived groove efficiency is 53.0%. To the best of our knowledge these are the highest values obtained yet at EUV wavelengths from a holographic ion-etched blazed grating.     

Fabrication and efficiency measurement of a multilayer-coated ion-beam-etched laminar grating for extreme ultraviolet region

We fabricate and measure a multilayer-coated ion-beam-etched laminar grating for the extreme ultraviolet wavelength region. The fabrication process is carefully controlled so that the grating groove and multilayercoating parameters well meet the design targets. At an incident angle of 10°, the peak diffraction efficiency of the ＋1st order is 20.6% at 14.56 nm and that of the -1st order is 22.1% at 14.65 nm, both close to the theoretical limits.     

Efficiency of a multilayer-coated, ion-etched laminar holographic grating in the 14.5 16.0-nm wavelength region

The efficiency of an ion-etched laminar holographic grating was measured at near-normal incidence in the 14.5-16.0-nm wavelength range. The grating had an electron-beam-evaporated Mo/Si multilayer coating matched to the grating groove depth. The efficiency peaked at 16.3% in the first inside order at 15.12 nm and 15.0% in the first outside order at 14.94 nm. These are believed to be the highest efficiencies obtained to date from a multilayer-coated laminar grating at near-normal incidence in the EUV (lambda<30.0nm) . Zero and even orders were almost completely suppressed. The grating groove efficiency in the first order approached the theoretical limit of 40.5%.     

MoRu-Be multilayer-coated grating with 10.4% normal-incidence efficiency near the 11.4-nm wavelength

A MoRu-Be multilayer coating was applied to a diffraction grating to enhance the grating's normal-incidence efficiency near 11.4 nm wavelength. The holographic grating substrate had a blazed groove profile with 2400 grooves/mm and a microroughness of 0.8 nm. The efficiency in the second diffraction order, measured with synchrotron radiation, was 10.4% at a wavelength of 11.37 nm.     

Fabrication of high-efficiency multilayer-coated binary blazed gratings in the EUV regime

Improving the efficiency of soft X-ray and extreme ultraviolet (EUV) gratings by way of multilayer reflection coatings has been under investigation for many years. Here we present the fabrication and characterization of binary blazed gratings designed to operate in the 14 nm wavelength region. These binary gratings are stepped approximations to the ideal sawtooth blazed-grating profile and are fabricated directly into a layer of photoresist. Normal-incidence reflection efficiencies as high as 25% into the first-diffracted order have been demonstrated.     

Molybdenum-strontium multilayer mirrors for the 8-12-nm extreme-ultraviolet wavelength region

Mo-Sr multilayer mirrors were successfully deposited by dc-magnetron sputtering and characterized in situ with synchrotron radiation. Normal-incidence (3.6 degrees ) reflectance of 23.0% at 8.8 nm, 40.8% at 9.4 nm, and 48.3% at 10.5 nm were measured before the samples were exposed to air. After exposure, as a result of the reactivity of Sr with oxygen and water vapor, the reflectance of these multilayers decreased rapidly. Attempts to use thin layers of C to passivate the surface of these Mo-Sr multilayers were unsuccessful.     

Direct measurement of index of refraction in the extreme-ultraviolet wavelength region with a novel interferometer

To the best of our knowledge, the first direct measurement of the dispersive part of the refractive index is performed at extreme-ultraviolet (EUV) wavelengths, where absorption is higher as compared with hard-x-ray and visible wavelengths. A novel diffractive optical element that combines the functions of a grating and a zone plate is fabricated with Fourier optical techniques and employed here for the first time at EUV/soft-x-ray wavelengths. Both the real and the imaginary parts of the complex refractive indices are measured directly by this technique without recourse to Kramers-Kronig transformations. Data for Al and Ni in the vicinity of their L and M edges, respectively, are presented as first examples of this technique.     

SiC/W/Ir multilayer-coated grating for enhanced efficiency in 50-100 nm wavelength range in Seya-Namioka mount

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.     

高损伤阈值矩形石英闪耀光栅的设计分析

 采用模态法分析了矩形亚波长石英闪耀光栅的设计原理,给出了1.06 μm工作波长的矩形亚波长石英闪耀光栅的设计示例。研究表明,要设计性能优良的-1级透射闪耀光栅,应使0/1阶传输模的累积相位差为π的奇数倍。设计的透射闪耀光栅能够使TM偏振光和TE偏振光获得近100%的-1级衍射效率,且具有较大的加工容差,较宽的入射波长和入射角变化适应范围。     

利用硅上倾斜V形槽结构制作闪耀光栅

以偏离〈100〉面25.24°的硅〈113〉晶面为基底,采用氧化、光刻等平面工艺,在其上制成光栅常数为36μm的二氧化硅光栅图形作掩模,用常规的硅各向异性腐蚀,在硅上形成连续倾斜的V形槽结构,制成槽距为36μm波长6328(?)时衍射效率达69%的闪耀光栅,进一步缩小槽距,可望获得实用的闪耀光栅.     

闪耀光栅光强分布的一种求解方法

以反射式闪耀光栅为例,提出了一种根据多孔夫琅禾费衍射性质来计算闪耀光栅夫琅禾费衍射光强分布的方法,得到的结果和教材完全一致.     

Design of a symmetric blazed grating sheet embedded in an autostereoscopic display

This study proposes a diffractive autostereoscopic display technology that utilizes blazed grating embedded in the liquid crystal panel to deliver a stereo image pair to both eyes. Having the diffractive red green blue beams as the color source of the panel, color filters are no longer required in this system. From the simulation analyses, not only could the brightness achieve 77.90%, but no serious chromatic aberration or cross talk appeared.     

Design and fabrication of planar blazed grating for LC rear-projection display system

Design and fabrication of planar blazed grating for single-panel LC rear-projection display system are presented. The structure of planar blazed grating is designed to disperse the incident visible light and achieve a high diffraction efficiency in a specified direction corresponding to a specified order. Two economical fabrication methods are studied. By ultrahigh-precision cutting technology, the continuous-relief planar gratings with the structure line width 0.96 and 1.5 μm are fabricated. In addition, other grating with the structure line width 2.5 μm is fabricated by using excimer laser dragging. Comparing the two fabrication results, the second one has smoother surface and smaller spacing error but the vertex angle is not enough sharp and the structure line width is limited.     

闪耀光栅阵列用于半导体激光器列阵光束整形

介绍了半导体激光器列阵的光束整形理论,设计并制作了由两个闪耀光栅阵列构成的整形光学系统,理论计算表明该系统能将激光器快、慢轴方向的光参数积变为5.7 mm·mrad和8.9 mm·mrad.在整形实验中测得变换后快、慢轴方向的光参数积分别为12 mm·mrad和9.5 mm·mrad,经透镜聚焦后能够实现与芯径200 μm,数值孔径0.22的光纤耦合.     

等腰闪耀光栅及其在非对称双光栅位移测量中的应用研究

本文简述了非对称双光栅位移测量的原理和特点,针对其中存在的一些问题,设计了一种新型透射式位相光栅———等腰闪耀光栅。文中导出了等腰闪耀光栅在垂直入射时的光栅方程和衍射光强分布公式,并通过计算机仿真,得到了衍射光强的分布图。最后探讨了等腰闪耀光栅在非对称双光栅位移测量中的应用     

Double groove silicon grating polarizer in telecommunication wavelength band

In this paper, we propose an ultra broad band polarizer operating in the telecommunication wavelength band, this device consisting a double groove silicon grating is designed with using the inverse mathematical method and rigorous vector diffraction theory. It is shown from our calculations that the device presents extremely high reflection (R > 95%) for TE polarization light and high transmission (T > 95%) for TM polarization over ∼400 nm wavelength range, moreover, the extinction ratio is ∼30 in the central wavelength 1550 nm. Furthermore, it is found with rigorous coupled wave analysis (RCWA) that the extremely wide band property for TE polarization is due to the excitation of strong modulation guided modes in the design wavelength range.     

Acoustic-induced switching of the reflection wavelength in a fiber Bragg grating

Coupling between copropagating core and cladding modes was implemented by acoustic generation of lateral vibration of an etched fiber. When these coupling processes were combined with counterpropagating coupling of a core mode and a cladding mode and the Bragg reflection of a fiber grating, switching of reflection wavelength between the Bragg wavelength and cladding-mode coupling wavelengths was achieved. We report the implementation of such acoustically induced switching behaviors and explain their operation principles. The implemented results can be used for wavelength-division multiplexed add-drop filtering.     

Thermally stable optical fibre Bragg grating wavelength reference

The inherent temperature dependence of optical fibre Bragg gratings is caused mainly by the positive thermo-optic effect of the fibre core material, and it results in an increase of Bragg wavelength with temperature. Special mounting techniques may be designed in order to compensate this thermo-optic effect by counter-acting effects: decreasing mechanical strain, as well as a decreasing effective refractive index for the guided light wave by evanescent field interaction with a liquid of negative thermo-optic effect. Because of the non-linear interaction characteristics, exact temperature compensation is obtained for a certain temperature, which depends on the design parameters. Such stabilised fibre Bragg gratings find application as wavelength references in Bragg grating sensor networks.     

分光计实验中光栅位置倾斜对测量谱线波长的影响

分3种情况讨论了光栅位置倾斜对测量谱线波长的影响,利用数学软件Mathematica作图估计其大小,并分别与仪器误差的影响作了比较,指出对于消减测量的系统误差,有些调整步骤是必要的,有些则是出于训练调整分光计的目的.     

用超声光栅测量氦氖激光的波长

介绍了一种新的测量激光波长的方法,并与传统的迈克耳孙干涉仪测量的结果进行了比较.我们对汞光和氦氖激光在乙醇(97%)形成的超声光栅中的衍射光谱进行了测量研究,首先利用汞光数据计算得到了超声波在乙醇中的传播速度,并分析了温度对结果的影响,然后利用超声波波速计算了氦氖激光的波长,得到的结果与标准值相比的相对误差为0.55%.此方法操作简便,且有与迈克耳孙干涉仪可比的精度.