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講座大師 - 第二十一屆 |
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| 沈元壤 |
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History of Light: Part Ity
光的歷史(一)
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This talk gives a brief history of light from the ancient time to the end of the 19th century. Light was mysterious, and worshipped in all civilizations in the ancient time. Ancient Greek philosophers first raised the question about the nature of light, but little progress was made for more than one and half millennia until the 17th century. Galileo’s telescope observation of the moons of Jupiter marked the beginning of optical science, and also the beginning of experimental science (scientific discovery requires experimental verification). The particle theory of light was first strongly advocated by Newton and generally accepted, but the wave theory of light later prevailed in the 19th century and was firmly established by the wave equations of Maxwell. Throughout those years, optical science spearheaded the development of physical sciences. The discovery of blackbody radiation, however, roused the controversy between particle and wave theories of light, which was finally resolved by the recognition of wave-particle duality nature of light and photons as light particles. This was the dawn of the quantum era, with light again leading the way. In the first half 20th century, optical science became mature and eager to find applications; it itself became dormant until lasers were born.
本演講簡介光的進展歷史，從古代到19世紀末期。在古代的所有文明中，光被認為是神祕的，也被崇拜。古希臘的哲學家首先探問光的性質，但在十七世紀前的長逾一千五百年期間，對光的理解進展很小。伽利略發明望遠鏡用以觀察木星的衛星，標記了光學的起始，也是實驗科學的起始(科學的發現需要實驗的驗證)。牛頓首先強力主張光的粒子說，獲得普遍的接受，但是後來在19世紀時，光的波動說卻佔了優勢，馬克士威還確立了光的波動方程式。在那些年代中，光學成為引導物理科學發展的先鋒。然而黑體輻射的發現，卻喚醒了光粒子說和波動說之間的爭論，最後則認定光是光子，具有粒子和波動的二象性，解決了爭議。這嶄露了量子紀元的曙光，光學再度領路前進。在二十世紀的前半葉，光學已經成熟並且廣泛運用，但光學本身的進展卻轉為沉伏，直至雷射興起。
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History of Light, Part II: A New Era of Optical Science
光的歷史(二)：光學的新紀元 |
The birth of lasers brought us to the current Modern Optics era that is still booming. The availability of coherent light sources over the entire broad spectral range from microwave to hard X-ray, with exceptionally high intensity or power, extremely narrow linewidth, diffraction-limited directionality, and ultrashort pulsewidth down to attoseconds, has led to a drastic changeover of optical science. A deeper understanding of the quantum nature of photons resulted in a flourishing field of quantum optics that has triggered the current research activities on quantum cryptography and quantum computation. On the broad scope, lasers have revolutionized nearly all areas of science and technology. They have made possible realization of highest pressure as well as both lowest and highest temperatures on earth, creation of coherent laser-like atomic beams, and detection of gravitational waves. Fifteen Nobel Prizes have been granted to laser-related discoveries or inventions since 1960, and more are likely to come. This talk will describe the progress of laser science and modern optics over the past 50+ years with selected topics and end with a brief perspective.
雷射的誕生帶領我們進入仍然蓬勃發展中的現代光學。現今可得的同調光源，其波長涵蓋全部廣大光譜的範圍，從微波到硬X射線，並具備有異常大功率或強度、極窄線寬、繞射限制的定向性、和小至阿秒(10-18s)的極短脈寬，已導致光學研究的激烈變革。對光子的量子性質的深入理解，促成了興盛的量子光學領域，催生了當前量子密碼和量子計算的研究。廣泛言之，雷射幾乎已革新了科學和技術的所有領域。雷射已實現在地球上所能生成的最大壓力以及最低和最高的溫度、造出類似雷射的同調原子束、和偵測重力波。自1960年以來，已有15個諾貝爾獎頒發給雷射相關的發現和發明，預期將來還會更多。本演講將精選若干主題，描述過去五十多年在雷射科學和現代光學的進展，最後以簡短的深入剖析作結。
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