Strahlungs-Emission und –Absorption nach der Quantentheorie (Radiation emission and absorption according to Quantum Theory) in Verhandlungen der Deutschen Physikalische Gesellschaft 18, pp. 318–323, 1916 [EINSTEIN’S 1st PAPER ON THE DERIVATION OF PLANCK’S LAW AS WELL AS HIS INTRODUCTION OF THE THEORY OF STIMULATED EMISSION]
Braunschweig: Druck und Verlag von Friedr. Vieweg and Son, 1916. 1st Edition. FIRST EDITION OF AN IMPORTANT WORK BY EINSTEIN: HIS FIRST PAPER ON THE DERIVATION OF PLANCK’S LAW, HERE INTRODUCING THE THEORY OF THE STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION INTO THE QUANTUM THEORY. “EINSTEIN’S CONCEPT OF STIMULATED EMISSION IS THE OPERATING PRINCIPLE OF THE NOW UBIQUITOUS LASER” (Brandt, Harvest of the Century, 136).
In 1900, Max Planck laid the foundation for quantum theory with his publication of Planck’s law. Though Einstein commended Planck, in his own “light-quantum hypothesis of 1905, [he, Einstein] postulated that the energy quantization is a property of the radiation field itself and not due to the material resonators [as Planck believed]” (ibid). “Einstein found a similarity between a cavity filled with radiation consisting of quanta and a vessel filled with gas consisting of atoms” (Brandt, Harvest of the Century, 136). Einstein believed that “although either part of Planck’s derivation was in itself consistent, their combination was logically incompatible…For Einstein this inconsistency was no reason to reject Planck’s quantum theory as such,” it was a reason to study the foundations of traditional radiation theory and if needed, revise them (Jammer, The Conceptual Development of Quantum Mechanics, 26).
“After completion of his general theory of relativity in 1916, Einstein was able to derive Planck’s original quantum law to his satisfaction “by considering the possible interactions between radiation and matter” (Brandt). From there, he was able to suggest that in addition to spontaneous emission and absorption, a process of stimulated emission could also take place.
In Einstein’s derivation of Planck’s law, he treats “the interaction between light quanta and atoms in the formalism of his A and B coefficients. They describe the probabilities for the absorption and emission of a light quantum of a given energy. The probability of absorption is, of course, proportional to the density of the radiation of that frequency. The emission is in part spontaneous, like radioactivity, but there is also stimulated emission which, again, is proportional to the density of the radiation of that frequency (ibid). This is one of two papers Einstein wrote on the subject.
Einstein’s derivation “predicted that as light passed through a substance it could stimulate the emission of more light. This effect is at the heart of the modern laser” (The Quantum and the Cosmos I, History, AIP portal). Item #1614
CONDITION & DETAILS: Braunschweig: Druck und Verlag von Friedr. Vieweg and Son. 8.5 x 6 in. [vi], 485, , 2, . 2. Ex-libris with few markings and non at the spine (see scan). Tightly bound. Brown cloth over marbled paper boards; gilt- ruled and lettered at the spine. Clean and bright throughout. Near fine. This volume is bound together with the 1916 volume titled Halbmonatliches Literaturverzeichnis der "Fortschritte der Physik" [Bi-monthly bibliography of the "Advances in Physics"].