共查询到19条相似文献,搜索用时 156 毫秒
1.
2.
3.
讨论了由激光束生成的环状干涉条纹用于目标成像的原理和使用匹配滤波器的处理方法,推导得出相应的点扩展函数(PSF)。模拟计算了主旁瓣峰值比和偏心量与相位量的关系,分析了偏心量对成像质量的影响。结果表明,适当的偏心量有利于提高环状干涉条纹成像的分辨率,又不致于产生对点扩展函数有影响的旁瓣。 相似文献
4.
5.
6.
菲涅耳双棱镜干涉在相衬成像和全息显微术中有重要应用。为了促进其应用,本文从信息光学角度研究双棱镜干涉,首先利用光场与脉冲响应函数之间的关系,理论导出了菲涅耳双棱镜干涉条纹强度公式,分析并讨论了狭缝缝宽及狭缝到双棱镜距离对菲涅耳双棱镜干涉条纹的影响,狭缝宽度大于0. 1 mm时,干涉条纹分辨率变差。接着给出了改变狭缝宽度(变化量为0. 08 mm)和改变狭缝到双棱镜的距离(从8 cm变化到12 cm)的实验结果,理论分析和实验结果一致。该结果有助于促进菲涅耳双棱镜干涉在相衬成像等领域的应用。 相似文献
7.
针对拼接式大口径望远镜主镜,提出一种基于迈克尔逊干涉原理基础上的宽带光谱(白光)干涉检测方法,对拼接子镜间相位误差进行实时检测,进而对失调子镜进行相应校正,以实现拼接子镜的共面排布。子镜间相位误差通过干涉图形间的不匹配性进行提取。应用双中心波长组合白光源来提高白光中心条纹的可见度,通过理论仿真,对不同中心波长组合的白光中心条纹可见度进行比较,结果表明:该双中心波长组合白光源系统的应用,可以提高白光干涉中心条纹的信号分辨能力,借以提高检测精度,使得该白光干涉检测系统对拼接子镜间的相位失调误差进行高精度提取。 相似文献
8.
针对拼接式大口径望远镜主镜,提出一种基于迈克尔逊干涉原理基础上的宽带光谱(白光)干涉检测方法,对拼接子镜间相位误差进行实时检测,进而对失调子镜进行相应校正,以实现拼接子镜的共面排布。子镜间相位误差通过干涉图形间的不匹配性进行提取。应用双中心波长组合白光源来提高白光中心条纹的可见度,通过理论仿真,对不同中心波长组合的白光中心条纹可见度进行比较,结果表明:该双中心波长组合白光源系统的应用,可以提高白光干涉中心条纹的信号分辨能力,借以提高检测精度,使得该白光干涉检测系统对拼接子镜间的相位失调误差进行高精度提取。 相似文献
9.
10.
以Matlab语言为基础,运用图像处理技术处理双棱镜干涉图像,较好地解决了实验中直边衍射带来的影响,得到单像素的干涉条纹,实现干涉条纹中心的精确定位和干涉条纹间距的精确测量. 相似文献
11.
12.
We have measured the spectral polarization-dependent losses of cascaded long-period fiber gratings composed of single, double, and triple identical gratings and fabricated by exposure of a UV laser beam on one side of a fiber. The measurement was made by use of the Mueller matrix method for scanning the wavelength of the incident beam. The polarization-dependent loss was dramatically increased as the number of cascaded gratings was increased. The formation of the UV-induced geometric birefringence in the fiber grating and its relationship to the fine interference fringes formed by cascading gratings are discussed. 相似文献
13.
14.
提出了一种利用45°半透半反分束镜和角锥反射器实现两路光纤激光器的能量相互注入,从而获得相干合成激光输出的新方法,分析了其锁相原理.在实验上成功实现了两路独立振荡双包层光纤激光器的互注入锁相输出,在远场观察到了清晰稳定的干涉条纹(可见度约0.57),获得了超过10W的相干合成激光输出,功率合成效率约为76%.实验表明,这种互注入锁相方法可以在更高功率条件下运行,是光纤激光相干合成领域一种有前途的新技术.
关键词:
光纤激光器
相干合成
互注入锁相 相似文献
15.
Beam width measurements of laser beams based on CCD by the second moment method as proposed by International Standardization Organization, are excessively sensitive to the noise far from light beam center. A novel method of noise elimination based on the analysis of the influence from CCD noise on laser beam width measurement result is proposed. The appropriate integral region could be obtained by genetic algorithm to improve accuracy of laser beam width measurement. The experimental results show that method could tolerate heavy CCD noise, and define the corresponding integral region according to requested precision. 相似文献
16.
光纤相控阵在激光合束、激光雷达等领域具有应用前景.光纤阵列配置方式不同于微波相控阵,光纤天线间距大于波长时存在周期旁瓣问题,影响主瓣能量分布.本文从物理模型出发,建立了基于同心圆环形点阵集合的光学相控阵天线布阵理论模型,提出了利用解析延拓的傅里叶变换方法实现干涉场强度的快速合成理论,讨论了在离散采样时数值仿真需关注的采样带宽和采样数目问题,解决了快速实现多光束干涉场数值仿真的问题.对比研究了两种优化光学相控阵天线配置的优化算法:遗传算法和粒子群算法,分别实现了不同种群数量遗传算法和粒子群算法迭代优化,分析了二者在优化过程中的收敛速度和优化效果,得到了峰值旁瓣比PSR=0.270的配置阵列.所提出的方法有望用于实际的光学相控阵天线配置中,指导天线主瓣能量最大化的优化设计;研究模型对不可微分目标函数优化问题的研究有一定参考价值. 相似文献
17.
We recently proposed a novel beam shaping technique that employs Lloyd’s mirror interference. In this study, we apply this
technique to three commercial laser diodes: laser diodes used for optical pumping of solid-state lasers, for laser beam printers,
and for laser displays. The elliptical output beams from these laser diodes could be transformed into nearly circular beams
by inserting a mirror-polished GaAs substrate below the active layer of each laser diode and adjusting its height. The experimentally
observed far-field patterns were predicted fairly well by numerical calculations based on Huygens’ integral. We confirmed
that our beam shaping technique is applicable to laser diodes with various wavelengths and vertical beam divergence angles.
We also describe the monolithic configuration of the beam shaping system, which can be fabricated by dry etching. 相似文献
18.
In this letter, we demonstrate coherent beam combination of laser diode array using the external Talbot cavity with double feedback. The double feedback elements consist of grating and high-reflection plane mirror. Compared with single high-reflection plane mirror feedback, the external Talbot cavity with double feedback reduce the number of interference strips in the far-field pattern and narrow spectral line-width of the laser diode array. The results indicate that the application of the external Talbot cavity with double feedback produces a clear far-field interference pattern. In addition, line-width is reduced to 0.15 nm full-width at half-maximum (FWHM). 相似文献
19.
Yoshio Hayasaki Maki Nishitani Hidetomo Takahashi Hirotsugu Yamamoto Akihiro Takita Daichi Suzuki Satoshi Hasegawa 《Applied Physics A: Materials Science & Processing》2012,107(2):357-362
In holographic femtosecond laser processing, diffractive parallel pulses are distorted by phase discontinuities and mutual
interference between the neighborhoods in the reconstructed image of a Fourier computer-generated hologram when the interval
is smaller than the beam diameter. We investigated holographic fabrication on a glass surface using parallel pulses with different
intervals. We found the closest parallel pulses with sufficient separation to avoid mutual interference in holographic femtosecond
laser processing. The minimum interval was 2.8 times larger than the diffracted beam diameter. The experimental results were
also supported by a computer simulation. Our findings will be very useful in the design of holographic laser processing systems. 相似文献