A Blast From The Past

[Packerbacker]

In a college textbook (PHYSICS For Students of Science and Engineering, Combined edition ), (c)1960, authors Robert Resnick and David Halliday feel so strongly about a certain subject that they print it in italics-- It is not possible to make two light sources coherent or even to make two parts of the same light source coherent.

This text was basically the first two semesters of collegiate physics.Naturally, the word laser, which was then in the process of invention, is not mentioned in the index.

Ho Hum, the "Laws of Physics."

 

[TheCigSmokingMan]

PB,

Are you saying all light is unrelated as according to the author?

TheCigMan

 

[Packerbacker]

No, the author is saying that a LASER is impossible, because the light emission, or photons, all come from different atoms, unlike microwave radiation that is generated by a fixed cavity(and hence the waves can be made in phase with one another).