诺贝尔奖与光学全息

Dennis Gabor’s 1948
• “The years after the war were the most fruitful. I wrote, among many others, my first papers on communication theory, I developed a system of stereoscopic cinematography, and in the last year, 1948 I carried out the basic experiments in holography, at that time called "wavefront reconstruction". “
3-D Holograph
Dynamic holography
全息照相原理 The Principles of Holography
全息照相：在感光片上记录物光的光 强分布，同时记录物光的位相分布， 并用 一定的手段再现出物体的立体图 象 全息照相原理：用干涉的方法记录物 光波，用衍射的方法再现物光波
• “After pondering this problem for a long time, a solution suddenly dawned on me, one fine day at Easter 1947” • “Why not take a bad electron picture, but one which contains the whole information, and correct it by optical means” • The interference of the object wave and of the coherent background or “reference wave” will then produce interference fringes.
Dennis Gabor’s words
• The original objective was an improved electron microscope, capable of resolving atomic lattices and seeing single atoms. • Three year's work, 1950-53, carried out in collaboration with the AEI Research Laboratory in Aldermaston, led to some respectable results, but still far from the goal. • We had started 20 years too early. • Only in recent years have certain auxiliary techniques developed to the point when electron holography could become a success. • On the other hand, optical holography has become a world success after the invention and introduction of the laser, and acoustical holography has now also made a promising start.
• First Holographic Reconstruction, 1948
• Holographic Reconstruction, 1948 • “the best of our series. It was far from perfect.”
• The disturbance arises from the fact that there is not one image but two.
诺贝尔奖与光学 Nobel Prize and Optics
全息
• The Doctor, an Emergency Medical Hologram Mark I (or EMH for short), from the television series Star Trek: Voyager.
1947年的电子显微镜
• 分辨率远高于光学显微镜，但是不能分辨原子 （Å ） • 快速电子波长～ 1/20 Å • “The best electron objective which one can make can be compared in optical perfection to a raindrop than to a microscope objective, and through the theoretical work of O. Scherzer it was known that it could never be perfected. The theoretical limit at that time was estimated at 4 Å .”
全息 Holography
全息与激光： 全息技术需要相干长度很长、 强度又较强的光源，激光满足此 条件，因而全息技术在激光发明 后得到迅速发展
全息记录光路图

P
PP
Real image Virtual image
Reconstruction beam Point-object hologram
点光源的 全息记录 和再现
参考光
物光
全息记录光路图
再现光
全息再现光路图(a)(b)a)全息底片图形，b)在显微镜下图形
全息记录底片和不同角度得到的再现象
全息分类
• Amplitude and phase modulation holograms • Transmission and reflection holograms
Later…
• In the course of three years we succeeded in considerably improving the electron microscope, but in the end we had to give up, because we had started too early. • It turned out that the electron microscope was still far from the limit imposed by optical aberrations. It suffered from vibrations, stray magnetic fields, creep of the stage, contamination of the object, all made worse by the long exposures required in the weak coherent electron beam. • Now, 20 years later, would be the right time to start on such a programme, because in the meantime the patient work of electron microscopists has overcome all these defects. The electron microscope resolution is now right up to the limit set by the spherical aberration, about 3.5 Å , and only an improvement by a factor of 2 is needed to resolve atomic lattices.
– cathode-beam oscillographs, electron microscopes and TV tubes
• joined the Siemens & Halske AG in 1927 • fled from Nazi Germany in 1933, • 1933-1948 work at the development department of the British ThomsonHouston company • 1949-1967 Imperial College of Science & Technology in London
全息？
3D投影， 还不是全 息。
全息 Holography
全息： “holo” = Whole 波所携带的全部信息 ——强度与位相 I=I0e-iwt
人物及时间
获奖原因
"for his invention and development of the holographic method". 1948年, Gabor为了提高电子显微 镜的分辨能力，发明了一种利用 干涉和衍射的照相新技术，记录 物体上各点光的完全信息:振幅和 位相，称这种技术为全息技术。 激光发明后，1962年第一张激光 全息图
Improvement
• “If an electron hologram is taken with a lens with spherical aberration, one can afterwards correct one of the two images by suitable optics, and the other has then twice the aberration, which washes it out almost completely.”
• Holography with Skew Reference Beam. • It was made possible by the great coherence length of the helium-neon laser.