共查询到20条相似文献,搜索用时 31 毫秒
1.
E. Neiss J.-L. Rehspringer L. Mager A. Fort J. Fontaine P. Montgomery M. Flury S. Robert 《Applied Physics A: Materials Science & Processing》2008,92(2):351-356
Ultraviolet laser machining of a hybrid organic/inorganic material prepared via a sol–gel process has been studied for the
fabrication of kinoforms or surface relief diffractive optical elements. The hybrid mixes silicon and titanium oxides and
an organic network in order to improve the mechanical properties. Different material compositions have been investigated.
Laser ablation of the hybrid material is observed at low laser fluence (measured threshold fluence of 125 mJ/cm2 at 248 nm/6 ns) and shows that the process is well adapted to micro-patterning by laser machining means. The best observed
depth resolution is 60± 20 nm and appears to be limited by the ablation setup. Finally, the fabrication of an effective diffractive
optical element and its operation at 1.06 μm are described.
PACS 81.20.Fw; 79.20.Ds; 42.79.-e 相似文献
2.
We demonstrate a compact optical correlator using a diffractive optical element (DOE) beam splitter for 2D optical image processing. Image frequency conversion and correlation are demonstrated using third-harmonic generation (THG) in an organic film with a 1550 nm femtosecond laser. Spatial and temporal alignment of the femtosecond pulses are obtained by imaging the DOE onto the organic film. 相似文献
3.
V. Kekkonen A. Hakola J. Likonen Y. Ge T. Kajava 《Applied Physics A: Materials Science & Processing》2012,108(2):423-430
Controlling laser-pulse parameters is an important issue in pulsed laser deposition (PLD). In particular, homogenization of laser beams improves the reproducibility of the PLD process by guaranteeing a uniform intensity distribution and a well-defined energy density of the laser spot on the target. We have integrated a beam-homogenization system into our PLD setup, and here we discuss the results and advantages of using such a system. The optical setup is based on diffractive beam-splitter gratings, which produce a 2×2-mm2 flat-top distribution with fluences of the order of 3 J/cm2 on the target. We demonstrate the applicability of this technique by depositing thin films of ferromagnetic Ni–Mn–Ga shape-memory alloys. Magnetic and structural characterization, including secondary ion mass spectrometry (SIMS), indicate that nearly stoichiometric composition and crystallization in the desired martensitic phase is obtained for films deposited on Al2O3 under optimal conditions. In contrast, the formation of silicide compounds at temperatures above 500 °C is detrimental in the deposition of Ni–Mn–Ga films directly on silicon. 相似文献
4.
A silicon nitride (SiNx) membrane diffractive optical element (DOE) designed to exhibit beam-splitting and focusing behavior at visible wavelengths has been fabricated and tested. Since the fabrication process is based on silicon micromachining technology, the DOE is easily integrated with a laser diode chip and a photodiode chip on a silicon substrate to function as the hologram-laser-photodiode unit for use in the pickup head of a CD or DVD system. The SiNx film is deposited with low-pressure chemical-vapor deposition and the free-standing membrane is formed by KOH etching. The transmissive DOE showed a high diffraction efficiency (>20% for a binary-phase-level element). The experimental evaluation was in good agreement with the designed and modeled predictions. 相似文献
5.
《中国光学快报(英文版)》2016,(5)
A method of multi-beam femtosecond laser irradiation combined with modified HF-HNO_3-CH_3 COOH etching is used for the parallel fabrication of all-silicon plano-concave microlens arrays(MLAs). The laser beam is split by a diffractive optical element and focused by a lens to drill microholes parallely on silicon. An HF-HNO_3-H_2SO_4-CH_3 COOH solution is used to expand and polish laser-ablated microholes to form microlenses. Compared with the HF-HNO_3-CH_3 COOH solution,the solution with H_2SO_4 can effectively reduce the etched surface roughness. The morphologies of MLAs at different laser powers and pulse numbers are observed. The image array formed by the silicon microlenses is also demonstrated. 相似文献
6.
We have designed, microfabricated, and characterized a diffractive optical element that reproduces the infrared spectrum of HF from 3600 to 4300 cm(-1) . The reflection-mode diffractive optic consists of 4096 lines, each 4.5mum wide, at 16 discrete depths relative to the substrate from 0 to 1.2 mum and was fabricated upon a silicon wafer by anisotropic reactive ion-beam etching in a four-mask-level process. We envisage the use of diffractive optical elements of this type as the basis for a new class of miniaturized, remote chemical sensor systems based on correlation spectroscopy. 相似文献
7.
Investigation of diffractive optical element for shaping a Gaussian beam into a ring-shaped pattern 总被引:1,自引:0,他引:1
To convert a given single-mode He–Ne laser beam into a ring-shaped intensity distribution, a diffractive optical element with 16 levels was designed by YG amplitude-phase retrieval and iteration algorithm. This beam shaper is investigated experimentally and compared with the results of the computer design. The results show good conformity, and the measured diffraction efficiency is 87.2%. In addition, the diffractive effect is observed when the distance between diffractive optical element and CCD is changed. 相似文献
8.
Using modularized components, we have built a miniaturized optical system for 87Rb atomic fountain clock that is fitted on an 80 cm × 60 cm optical breadboard. Compared with the conventional optical setup on the table, our system is more compact, more robust and miniaturized. Taking advantage of this system, laser beams are transmitted through eight optical fibre patch cords from the optical breadboard to an ultra high vacuum system. This optical setup has operated for five months in our fountain system and required no alignment. 相似文献
9.
A. N. Agafonov M. G. Vlasenko B. O. Volodkin V. V. Gerasimov A. K. Kaveev B. A. Knyazev G. I. Kropotov V. S. Pavelyev I. G. Palchikova V. A. Soyfer M. F. Stupak K. N. Tukmakov E. V. Tsygankova Yu. Yu. Choporova 《Bulletin of the Russian Academy of Sciences: Physics》2013,77(9):1164-1166
Techniques for manufacturing silicon binary (two-level) diffractive lenses and polypropylene kinoform diffractive lenses for the terahertz spectrum range are described. The elements are 1 and 0.8 mm thick, respectively. The silicon lens is manufactured in two versions: with no coating and with a parylene C (polyparaxylylene) antireflection coating. Characteristics of the diffractive optical elements are studied in the beam of a pulse-periodic free electron laser at a radiation wavelength of 141 μm and a repetition rate of 5.6MHz. The radiation resistance of the parylene coating, tested on the Novosibirsk free electron laser, was not impaired when the coating was exposed to an average power density of 4 kW cm?2, the peak power in a 100-picosecond pulse being almost 8 MW cm?2. 相似文献
10.
We report a beam-delivery system consisting of a non-digitized diffractive beam splitter and a Fourier transform lens. The system is applied to the deep-drilling of silicon using a nanosecond pulse laser in the manufacture of inkjet printer heads. In this process, a circularly polarized pulse beam is divided into an array of uniform beams, which are then delivered precisely to the process points. To meet these requirements, the splitter was designed to be polarization-independent with an efficiency>95%. The optical elements were assembled so as to allow the fine tuning of the effective overall focal length by adjusting the wavefront curvature of the beam. Using the system, a beam alignment accuracy of<5 μm was achieved for a 12-mm-wide beam array and the throughput was substantially improved (10,000 points on a silicon wafer drilled in ~1 min). This beam-delivery scheme works for a variety of laser applications that require parallel processing. 相似文献
11.
在折衍混合光学系统的加工和装配过程中,折、衍器件间的对中精度严重影响混合器件的质量和性能,但是由于衍射器件与传统折射器件的显着差异,传统的对中手段已不再适用,如何简便实现二者的精确对中是混合光学系统实用化过程中亟待解决的问题之一.本文提出利用干涉原理简便地实现衍射器件与折射器件的高精度对中,理论分析和实验结果表明该对中装校方法是有效可行的,可以满足光学系统的对中要求。 相似文献
12.
We describe the fabrication and characterization of a nanostructured diffractive element with near-zero reflection losses. In this element, subwavelength nanostructures emulating adiabatic index matching are integrated on the surface of a diffractive microstructure to suppress reflected diffraction orders. The fabricated silicon grating exhibits reflected efficiencies that are suppressed by 2 orders of magnitude over broad wavelength bands and wide incident angles. Theoretical models of the fabricated structure based on rigorous coupled-wave analysis and effective medium theory are in agreement with the experimental data. The proposed principles can be applied to improve the performance of any diffractive structures, potentially leading to more efficient Fresnel lenses, holographic elements, and integrated optical systems. 相似文献
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14.
S. Vogt C. Lisdat T. Legero U. Sterr I. Ernsting A. Nevsky S. Schiller 《Applied physics. B, Lasers and optics》2011,104(4):741-745
We present the setup and test of a transportable clock laser at 698 nm for a strontium lattice clock. A master-slave diode
laser system is stabilized to a rigidly mounted optical reference cavity. The setup was transported by truck over 400 km from
Braunschweig to Düsseldorf, where the cavity-stabilized laser was compared to a stationary clock laser for the interrogation
of ytterbium (578 nm). Only minor realignments were necessary after the transport. The lasers were compared using a Ti:Sapphire
frequency comb as a transfer oscillator. The generated virtual beat showed a combined linewidth below 1 Hz (at 1156 nm). The
transport back to Braunschweig did not degrade the laser performance, as was shown by interrogating the strontium clock transition. 相似文献
15.
The adjustment effort required for the alignment of laser resonators with arbitrarily shaped end mirrors can be significantly reduced by folding the resonator path half-way between the two end mirrors and by slightly tilting the resonator axis. Thus the resulting resonator consists only of one diffractive mirror and a plane mirror, and the separate alignment of both diffractive end mirrors with respect to each other can be avoided. This principle is demonstrated by a Nd:YAG laser with super-Gaussian output beam. Furthermore, it is shown theoretically that the influence of phase quantization effects on the beam quality can be strongly reduced as a consequence of the tilted resonator axis. 相似文献
16.
A diffractive optical element (DOE) is applied to effectively locate a laser pointer spot on a projection screen for laser pointer interaction applications. The DOE is placed in front of a digital web camera to blur the background image while transforming the laser spot into a large diffractive pattern, such as a circle. To calculate the diffractive pattern position on the screen, only a simple subtraction method using two successive digital images with the laser ON and OFF, respectively, is needed. This approach also improves the compressed digital image transmission latency. 相似文献
17.
针对多次曝光法制作集成衍射光学元件时存在的加工制作复杂,会引入较大的对位误差等问题,基于计算全息中的误差扩散编码原理及部分相干光成像理论,提出采用误差扩散编码方法来设计用于制作浮雕结构集成元件的编码掩模的新方法。给出了利用误差扩散法设计的色分离光栅-光束采样光栅(CSG-BSG)集成元件编码掩模,模拟计算了经部分相干成像系统后的空间像光强分布,并与理想的集成元件面形进行了比较。结果表明,校正后均方差为7.5%,体积偏差为10.2%。 相似文献
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19.
The application of electron-beam lithography to the generation of diffractive optical elements topology is examined. The formula for the estimation of exposure data volume for variable-shaped electron-beam lithography is presented as a function of diffractive optical element parameters and approximation accuracy. A special software dedicated to preparing exposure data for fabrication of diffractive optical elements is developed. Diffractive optical elements with an artificial refractive index are manufactured with a feature size much less than the wavelength. Design and experimental results on photomasks fabrication for an optical element focusing radiation into a ring with pregiven parameters are presented. The photomask set is manufactured for a reflecting optical element focusing the high power CO2 laser beam into two points with required parameters for laser welding. 相似文献
20.
We propose a new approach to generating a pair of initial beams for a polarization converter that operates by summing up two opposite-sign circularly polarized beams. The conjugated pairs of vortex beams matched with laser modes are generated using binary diffractive optical elements (DOEs). The same binary element simultaneously serves two functions: a beam shaper and a beam splitter. Two proposed optical arrangements are compared in terms of alignment complexity and energy efficiency. The DOEs in question have been designed and fabricated. Natural experiments that demonstrate the generation of vector higher-order cylindrical beams have been conducted. 相似文献