共查询到20条相似文献,搜索用时 46 毫秒
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We propose dispersive coherence spectrotomography with white-light continuum to extract both range and spectral properties inside a medium. The main feature is that the dispersive coherence spectrotomography has a high dynamic range in depth and high signal-to-noise ratio making the most of the extreme brightness of the white-light continuum. 相似文献
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In low-coherence reflectometry, light scattered back from a medium is expected to contain spectral properties as well as range information on the reflective boundaries and backscattering sites. Low-coherence interferometric systems with particular signal-processing techniques have been proposed that can extract both the range and spectral properties inside the medium simultaneously. This class of systems is called coherence spectrotomography. In this paper, basic principles of coherence spectrotomography are reviewed referring to the experimental results on multi-layered media. 相似文献
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We generated a white-light continuum array by directing femtosecond laser pulses into a liquid with a microlens array. Experimental evidence demonstrates that the spatial coherence is high within a single light source in the array. We also confirmed that all the light sources in the white-light continuum array are mutually coherent. We found that the simple self-phase modulation model cannot explain this high coherence between the white continuum sources. 相似文献
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EunSeo Choi Young-Jae Kim Jihoon Na Changsu Lee Changsu Na Byoeng Ha Lee 《Optical Review》2003,10(6):576-579
Optical Coherence Tomography (OCT) is considered as fundamentally new image modality having advantages such as high-speed, real-time cross sectional imaging with non-invasive in vivo investigation of biological tissue and its potential for clinical application is highly evaluated. In spite of these merits, the research activity in OCT has not taken much attention until recently. However the situation in Korea is gradually changing due to understanding of its versatile applications. Active research and commercialization are underway. Bulk optics-based OCT system is changed into alignfree fiber-optics system. With our expertise in the fabrication of fiber grating devices and strong background in control of fiber based system, we hope to contribute in developing simplified all-fiber OCT system with better performance. As a leading research group, working on OCT, we have firstly implemented fiber-based OCT system in Korea and demonstrated the imaging performance with glass plate and onion. 相似文献
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光纤白光干涉技术的回顾与展望 总被引:1,自引:0,他引:1
光纤白光干涉技术与方法是光纤技术领域中独具特色的一种测量方法和传感技术,是光纤技术多领域交叉应用中较为有代表性的一个分支.该项技术在宽谱光干涉特性研究、绝对形变光纤传感测量、光波导器件的结构及其对光波反射特性参量的检测、光纤陀螺环中光偏振态横向耦合测量与评估以及医学临床诊断的组织结构形态的光学层析技术等方面,都具有广泛... 相似文献
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Yoshiaki Yasuno Yasunori Sutoh Shuichi Makita Masahide Itoh Toyohiko Yatagai 《Optical Review》2003,10(5):498-500
A spectral interferometric optical coherence tomography (OCT) system which has polarization sensitivity is developed. This system reduces the mechanical scanning dimension by employing the principle of spectral interferometry, and measures a two dimensional cross-sectional image of biological tissue with one dimensional mechanical scanning. Sixteen OCT images with different polarization conditions are measured, and two dimensional distributions of each element of the Müller matrix of a sample to be measured are calculated. 相似文献
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垂直扫描白光干涉术用于微机电系统的尺寸表征 总被引:4,自引:0,他引:4
随着微机电系统的发展,器件设计和加工过程中的表征成为一个主要问题。提出了将扫描白光干涉表面轮廓测量方法用于微结构和器件的几何特性检测上。测量系统采用了米劳显微干涉仪,利用压电陶瓷物镜纳米定位器实现垂直方向100μm范围内的精确扫描,并通过傅里叶变换算法获取条纹包络峰的位置,进而得到器件的整体集合尺寸信息,与相移干涉方法相比大大提高了测量范围。通过测量纳米台阶对该系统进行了精度标定,测量重复性在亚纳米量级。最后通过测量微谐振器和微压力传感器的几何尺寸说明了该方法的功能。 相似文献
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基于观察矩阵的频域光学相干层析成像图像重构算法 总被引:2,自引:0,他引:2
频域光学相干层析成像技术是一种新型的医学成像技术,其传统的图像重构算法主要是基于傅里叶变换。但这种重构算法的主要缺陷在于其纵向分辨率随着深度位置的变化而明显下降。为了使频域光学相干层析成像系统的纵向分辨率在整个成像深度内基本保持不变,提出了一种基于观察矩阵的图像重构法,并用该法重构了平面镜以及皮肤信号。结果表明,这种图像重构法能够使频域光学相干层析成像系统保持纵向分辨率不变。与文献报道相比,这种方法在保持系统简单性的同时,还保持了高的纵向分辨率,并在成像深度范围内使得纵向分辨率基本保持不变。 相似文献
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We present a non-scanning approach for real-time optical coherence tomography (OCT). Our approach is based on an off-axis interferometer that laterally projects the time-of-flight or depth information of the sample onto an image sensor. To facilitate the use of an off-axis interferometer in OCT, an angular-dispersion imaging method has been developed. Theoretical analysis and experimental results are presented to demonstrate that this method is capable of demodulating the interferogram and thus permits a direct inspection of the depth-resolved image. Depth resolution and detection range of the present method are also studied. 相似文献
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利用变迹术和相干门相结合实现光学相干层析成像术轴向超分辨 总被引:4,自引:2,他引:2
光学相十层析成像(光学相干层析成像术)的轴向分辨力由光源带宽和探测光束的聚焦条件共同决定。提高光学相干层析成像术轴向分辨力的方法主要基于带宽光源技术。提出了一种将变迹术与光学相十层析成像术相干门有机结合的方法来提高其轴向分辨力。通过适当形式的光瞳滤波器.使光学相干层析成像术系统轴向响应的主瓣宽度缩小到相干门之内,而其旁瓣则处于相干门之外.不对相干成像产生有效贡献。这样.就能在光源带宽不变的条件下,有效提高光学相十层析成像术的轴向分辨力,避免了采用宽带光源所带来的费用昂贵和系统复杂等缺陷。 相似文献
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M. Tassou C. Przygodzki H. Delbarre D. Boucher 《International Journal of Infrared and Millimeter Waves》2002,23(8):1227-1239
We investigate a new experimental method for detecting molecules from the ultraviolet to the near infrared range using ultrashort laser pulses. Two types of sources are used: a white light continuum generated by 200khz Ti: Sapphire regenerative amplifier system, and a near-gaussian femtosecond pulse (100 fs) generated by an optical parametric amplifier and tunable from 0.45 to 2.4 m. Up to now, this technique has only been performed in the visible domain. Both broadband sources allow the detection of the oxygen and the water vapor bands. Moreover, a new extraction method has been implemented, which provides the molecules' concentration by using a nonlinear fit technique. 相似文献
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A needle-fiber optical coherence tomography (OCT) system designed for guiding epidural anesthesia to a target is presented.
In the preliminary experiment, a desired target in tofu as a strong scattering medium can be monitored over a sufficient range of several millimeters within a short measuring time.
The axial resolution is 21 μm. In order to investigate the ranging performance, the relation between background noise levels
and focus-scattering properties in a confocal optical system is numerically studied by use of Monte Carlo technique. Numerical
results indicate that an appropriate focal length of the lens attached to the fiber should be used to separate the OCT signal
from strong noise in strongly scattered medium. 相似文献
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光学相干层析系统相干传递函数研究 总被引:4,自引:1,他引:4
在弱物体近似下从成像系统角度对光学相干层析测量技术进行了理论研究。分析了该技术测量样品纵深结构时图像的形成机理。结果表明它相当于一复振幅线性平移不变系统,从而可用相干传递函数描述系统性能,所得相干传递函数表明系统具有低通特性,半峰值带宽△k=2△λ/λ^2。由于物体频谱整体平移了1/λ,测量的是纵向结构的高频信息。本文的工作为定量分析光学相干层析对未知结构的测量结果及进一步提高空间分辨率提供了理论 相似文献
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An imaging interferometer with two long gradient-index (GRIN) lenses and a charge coupled device (CCD) sensor array is proposed and studied for application to an optical coherence tomography system that can observe the subsurface structure of internal organs through a small hole in the body. An image of lines 11 μm wide was obtained using the phase-shifting method and a test pattern as a sample. The lateral resolution obtained was 22 μm. The axial resolution was also measured and found to be 19.4 μm by measuring the coherence function. The dynamic range was about 60 dB, based on the RF spectrum of the beat signal. A sectional image of a 10-yen Japanese coin was measured as a rough surface sample. 相似文献