量子力学对发明激光的阻碍作用

[verdelite]

激光（laser）发明之前先有Maser，微波波段的激光。Maser发明后，大家纷纷研究怎么做激光。Maser是Townes发明的。这本书里“The Laser in America: 1950 - 1970”（google books 有preview）里面描述了量子力学对maser发明的阻碍作用：

（Background: 美国为了搞微波雷达，委派Townes组织研究分子微波振荡是否可行。在1951年他想出来一个主意，怎样才能做成分子微波振荡器，也就是maser。当时的物理学家都觉得不行，幸好他坚持自己的做法，找人找资源于1953年把maser做出来了）quote:
“
...Most physicists he spoke to were far from ready to be swayed by analogies between ammonia molecules in a resonant cavity and regenerative oscillators. Instead, they argued from the uncertainty principle of quantum mechanics that the degree of monochromaticity that Townes expected was impossible. Townes reported, "I never succeeded in convincing two of my Columbia University colleagues, even after long discussion, that the frequency width could be very narrow....After successful oscillation, I remember interesting discussions on this point with Niels Bohr and with [John] von Neumann. Each immediately questioned how such a narrow frequency could be allowed by the uncertainty principle."[17 ] Townes has also pointed out that physicists in this period were mainly interested in electromagnetic radiation in the visible region, where it was more useful to think of radiation in terms of photons (discrete packages of energy) than in terms of waves. But the coherence of two streams of radiation is most naturally thought of in terms of waves. "Emphasis on the photon aspect of light deflected some physicists from coherent amplification," Townes writes. "In thinking about light itself rather than microwaves, it may be that many electrical engineers would have not been any more concerned with coherence effects than were these physicists."[18]
”

事实是量子力学对激光的发明是起了阻碍作用。最好不要再用量子力学来碰瓷激光了。

[TheMatrix]

有意思。

对物理理论还是要采取实用态度 - 勇于抛弃。

[Caravel]

有意思。

对物理理论还是要采取实用态度 - 勇于抛弃。

Verdlite的解读角度太搞笑了, Maser和Laser的名字就证明了他们都是stimulated emission of radiation，就是1917年爱因斯坦发现的。没有量子力学，能做出来么。

物理是很复杂的，你找两个大佬聊十分钟，人不就跟你敷衍两句测不准原理

[verdelite]

Verdlite的解读角度太搞笑了, Maser和Laser的名字就证明了他们都是stimulated emission of radiation，就是1917年爱因斯坦发现的。没有量子力学，能做出来么。

物理是很复杂的，你找两个大佬聊十分钟，人不就跟你敷衍两句测不准原理

量子力学一直处于“解释”地位。coherent radiation, 量子力学说是stimulated radiation，别人说是resonance。

量子力学原理里有，而别的理论里没有的东西，做出来的预测，比如量子计算，量子通信，都不成功。

[Caravel]

量子力学一直处于“解释”地位。coherent radiation, 量子力学说是stimulated radiation，别人说是resonance。

量子力学原理里有，而别的理论里没有的东西，做出来的预测，比如量子计算，量子通信，都不成功。

不是，根据WIKI的解释，MASER的idea 是由 Joseph Weber，这是他的访谈

https://www.aip.org/history-programs/ni ... ories/4941

Weber:
Catholic University is an absolutely superb educational institution, one of the finest places I have ever been privileged to attend. Dr. Karl Herzfeld gave excellent lectures. One had only to take notes. The notes were easily read and understood. One of my courses was atomic physics. It was a two hour, one afternoon a week, lecture during the academic year 1948-1949. It began in September 1948, and ended in June 1949.

One of the lectures which Dr. Herzfeld gave was on Einstein's 1917 deduction of the Planck radiation law, in which he introduced his A and B coefficients, and discussed stimulated and spontaneous emission. During that lecture, it was immediately obvious to me that the stimulated emission idea could be used to make a microwave amplifier and generators.


From the time of that lecture, I thought actively and worked actively on the project, and submitted a summary of my research to the first available conference which I thought would have any interest in it. This was the 1952 Institute of Radio Engineers Vacuum Tube Research Conference at Ottawa. The paper was submitted in 1951 for the June 1952 program. Professor Herbert J. Reich of Yale University was on the papers committee. He was also editor of the TRANSACTIONS of the Institute of Radio Engineers Professional Group on Electron Devices. He wrote to me, after the Ottawa conference, asking permission to publish a summary which I had submitted in 1951 for publication.

[verdelite]

不是，根据WIKI的解释，MASER的idea 是由 Joseph Weber，这是他的访谈

https://www.aip.org/history-programs/ni ... ories/4941

Weber:
Catholic University is an absolutely superb educational institution, one of the finest places I have ever been privileged to attend. Dr. Karl Herzfeld gave excellent lectures. One had only to take notes. The notes were easily read and understood. One of my courses was atomic physics. It was a two hour, one afternoon a week, lecture during the academic year 1948-1949. It began in September 1948, and ended in June 1949.

One of the lectures which Dr. Herzfeld gave was on Einstein's 1917 deduction of the Planck radiation law, in which he introduced his A and B coefficients, and discussed stimulated and spontaneous emission. During that lecture, it was immediately obvious to me that the stimulated emission idea could be used to make a microwave amplifier and generators.


From the time of that lecture, I thought actively and worked actively on the project, and submitted a summary of my research to the first available conference which I thought would have any interest in it. This was the 1952 Institute of Radio Engineers Vacuum Tube Research Conference at Ottawa. The paper was submitted in 1951 for the June 1952 program. Professor Herbert J. Reich of Yale University was on the papers committee. He was also editor of the TRANSACTIONS of the Institute of Radio Engineers Professional Group on Electron Devices. He wrote to me, after the Ottawa conference, asking permission to publish a summary which I had submitted in 1951 for publication.

我引用的书里也谈了Weber, 他是同时期的，做分子放大微波信号的。和做振荡就只差了一个反馈。

[verdelite]

我引用的书里也谈了Weber, 他是同时期的，做分子放大微波信号的。和做振荡就只差了一个反馈。

关于谁发明了maser，这本Brotherton的书《Masers and Lasers》里面说(page 199)：

"The idea of harnessing the orbital energy of atoms and molecules for useful amplification occurred independently to several workers in the microwave field, notably to C. H. Townes, then to Columbia University, to N. G. Basov and A. M. Prokhorov in the U.S.S.R., and to J. Weber of the University of Maryland. However, it was C. H. Townes who first saw how to make an actual device. In 1954 he built, in cooperation with J. P. Gordon and H. J. Zeiger, the first of all masers using ammonia gas and operating at microwave frequencies."

[Caravel]

关于谁发明了maser，这本Brotherton的书《Masers and Lasers》里面说(page 199)：

"The idea of harnessing the orbital energy of atoms and molecules for useful amplification occurred independently to several workers in the microwave field, notably to C. H. Townes, then to Columbia University, to N. G. Basov and A. M. Prokhorov in the U.S.S.R., and to J. Weber of the University of Maryland. However, it was C. H. Townes who first saw how to make an actual device. In 1954 he built, in cooperation with J. P. Gordon and H. J. Zeiger, the first of all masers using ammonia gas and operating at microwave frequencies."

不知道是谁起的名字MASER，起名字的人肯定就知道了stimulated radiation