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研制了不同厚度的直径为5-15μm的GaN光学微盘,并 学微盘的显微荧光图像进行了细致观测和数据值采集。结果表明,在同一个GaN外延样品上由于厚度的差别,微盘呈现两种不同类型的荧光图像, 相似文献
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折射型微透镜列阵的光刻热熔法研究 总被引:8,自引:1,他引:7
研究了制作折射型微透镜列阵的一种新方法光刻胶热熔成形法,获得了20×20的折射型微透镜列阵,单元微透镜相对口径为F/2,单元透镜直径为90μm,中心间隔100μm,透镜的波像差小于1.3波长。本文详细阐述了光刻热熔法的基本原理及微透镜设计方法,并讨论了工艺参数对微透镜列阵质量的影响。 相似文献
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用于受激光散射实验的光学多道分析器 总被引:1,自引:0,他引:1
使用自制的以CCD成像器件为探测器的简易光学多道分析器完成了受激光散射谱的系集与处理。该多过分析器空间分辨率14μm,灵敏度0.1LX,给出了装置的设计以及所得到的谱图 相似文献
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输出红光的电子俘获材料及其在图像存储和减法中的应用 总被引:9,自引:2,他引:7
研究了输出红光的电子俘材料的光学性质和物理机制。利用-200μm厚的电子俘获薄膜在实验上证明了图像存储和图像减法的可能性。实验表明,这种材料对光存储和光学信息处理应用,具有很多有吸引力的优点,如:可擦除,可重写,高分辨,高速度,以及模拟和并行操作等。 相似文献
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大型光学综合口径望远镜的新方案 总被引:2,自引:0,他引:2
建议一台4.3m光学红外新技术望远镜,并与北京天文台2.16m望远镜用真空管道联机集像作CCD照相和光干涉测量,提高焦光能力达4.8m口径,分辨率可接近10余米口径。 相似文献
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扩展微透镜数值孔径范围的阶梯光刻热熔法研究 总被引:4,自引:1,他引:3
在微透镜阵列的光刻热熔制作法中,临界角效应严重影响了微透镜的制作范围和面形质量。在对临界角效应定性研究的基础上,提出了用阶梯光刻熔法来扩展热熔型微透镜阵列的数值孔径范围。实验结果表明,采用这一方法制作的微透镜,其单元孔径范围扩展为50 ̄900μm,相对口径范围扩大到为F/1 ̄F/10,并有效地改善了临界角效应对大孔径微透镜面形质量的影响。 相似文献
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The research on the setup and application of scanning near-field optical microscopy (SNOM) performed in our laboratory is reviewed in this report. We have constructed a versatile low temperature scanning near-field optical microscope with the capability of near-field imaging and spectroscopy, operating at liquid nitrogen temperature. A special designed coaxial double lens was used to introduce the illumination beam through a 200μm fiber; the detected optical signal was transmitted via a fiber tip to an avalanche photon detector. The performance test shows the stability of the new design. The shear force image and optical image of a standard sample are shown. A system of SNOM working at room temperature and atmosphere was used to characterize semiconductors and bio-molecular samples. It revealed the unique features of semiconductor microdisks in the near-field that is significantly different from that of far-field. The effects of different geographic microstructures on the near-field light distribution of InGaP, GaN, and InGaN multi-quantum-well microdisk were observed. 相似文献
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A fiber taper can evanescently couple to whispering gallery modes (WGMs) in a planar silica microdisk for observing the optical properties of the microdisk cavity. It is revealed that WGMs have very high quality (Q) factors by controlling the air gap between the taper and the microdisk. The best coupling efficiency from the taper to the microdisk is as high as 98%, and can be continuously adjusted from the under-coupling, critical-coupling to over-coupling regimes. The influence of the laboratory circumstance such as surface contamination on the microdisk is also discussed. It is experimentally shown that the high-Q-factor (105) modes can be kept for a long period in a general laboratory circumstance. 相似文献
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Quality factor enhancement due to mode coupling is observed in a three-dimensional microdisk resonator. The microdisk, which is vertically sandwiched between air and a substrate, with a radius of 1 microm, a thickness of 0.2 microm, and a refractive index of 3.4, is considered in a finite-difference time-domain (FDTD) numerical simulation. The mode quality factor of the fundamental mode HE71 decreases with an increase of the refractive index of the substrate, n(sub), from 2.0 to 3.17. However, the mode quality factor of the first-order mode HE72 reaches a peak value at n(sub) = 2.7 because of the mode coupling between the fundamental and the first-order modes. The variation of mode field distributions due to the mode coupling is also observed. This mechanism may be used to realize high-quality-factor modes in microdisks with high-refractive-index substrates. 相似文献
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Blaize S Gesuele F Stefanon I Bruyant A Lérondel G Royer P Martin B Morand A Benech P Fedeli JM 《Optics letters》2010,35(19):3168-3170
We report on the real-space observation of resonant frequency splitting in a high-Q waveguide-coupled silicon-on-insulator microdisk resonator. Phase sensitive near-field analysis reveals the stationary nature of the two resonant states, and spectral investigations clearly show their orthogonality. These measurements emphasize the role of the coupling waveguide in this splitting phenomenon. The symmetry of the two stationary whispering gallery modes is clearly observed and is found to follow the axial symmetry of the waveguide-coupled microdisk as it has been reported by earlier theoretical predictions. 相似文献
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Silica whispering gallery mode(WGM) microcavities were fabricated by the buffered oxide etcher and potassium hydroxide wet etching technique without any subsequent chemical or laser treatments. The silicon pedestal underneath was an octagonal pyramid, thus providing a pointed connection area with the top silica microdisk while weakly influencing the resonance modes. The sidewalls of our microdisks were wedge shaped, which was believed to be an advantage for the mode confinement. Efficient coupling from and to the 60 μm diameter microdisk structure was achieved using tapered optical fibres, exhibiting a quality factor of 1.5×10~4 near a wavelength of 1550 nm. Many resonance modes were observed, and double transverse electric modes were identified by theoretical calculations. The quality factor of the microdisks was also analysed to deduce the cavity roughness. The wet etching technique provides a more convenient avenue to fabricate WGM microdisks than conventional fabrication methods. 相似文献
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Microdisk resonator filters, an alternative to microring resonator filters, are studied by means of vectorial three dimensional finite element method simulations. Their performance characteristics are highlighted for different microdisk radii, and compared with those of the respective, footprint-wise, microring filters. We show that microdisk filters are advantageous, as the resonator involved exhibits smaller radiation losses. Extinction ratios as high as 30 dB are possible by properly tuning the gap separating the waveguide from the microdisk in each case. Transmission dips due to higher-radial-order modes that drastically change the transmission picture appear only for very large microdisk radii. 相似文献
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We numerically investigate the behavior of Whispering Gallery Modes (WGMs) in circularly shaped resonators like microdisks, with diameters in the range of optical vacuum wavelengths. The microdisk is embedded in an uniaxial anisotropic dielectric environment. By changing the optical anisotropy, one obtains spectral tunability of the optical modes. The degree of tunability strongly depends on the radial (azimuthal) mode order M (N). As the modes approach each other spectrally, anticrossing is observed, leading to a rearrangement of the optical states. 相似文献
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We report planar waveguide-coupled octagonal microdisk channel add-drop filters on silicon nitride-on-silica substrates. Using ray optics, we show that discrete octagonal cavities have wave-front-matched four- and eight-bounce ray orbits. From a planar waveguide-coupled 50-microm-sized octagonal microdisk filter, our experiment demonstrates TM-polarized eight-bounce modes with a coupling efficiency of approximately 56%, Q approximately equal to 1150, and a finesse of approximately 5. Using the two-dimensional finite-difference time-domain method, we obtain qualitative agreement between measurement and simulation of a smaller-sized waveguide-coupled octagonal microdisk filter. 相似文献
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We propose and experimentally demonstrate a dual-band optical filter based on a single microdisk resonator. An analytical model is built based on the transfer matrix method and is applied to simulate the properties of such a device. Competition and interference of the dual modes in the resonator lead to dual-band filtering with high isolation. As the finite-difference time-domain simulation illustrates, two low-order resonant modes can be effectively triggered by optimizing the waveguide width and spacing gap between the compact resonator and waveguides. In experiment, a double side-coupled microdisk resonator was fabricated on a nanophotonic silicon-on-insulator platform, and dual-band bandpass filtering is realized with an optical isolation higher than 20 dB and an insertion loss lower than 2 dB. The experimental results agree well with our modeling results. 相似文献