Spectroscopic Foundations of Lasers: Spontaneous Emission Into a Resonator Mode
2015 (English)In: IEEE Journal of Selected Topics in Quantum Electronics, ISSN 1077-260X, E-ISSN 1558-4542, Vol. 21, no 1, 9000216- p.Article in journal (Refereed) Published
We review the physics underlying the process of spontaneous emission, with a special focus on spontaneous emission into a resonator mode. We define the mode volume, verify the fundamental modal dimensions, present the spectral mode profile, the coherence time, the Q-factor, the Fuchtbauer-Ladenburg equation, and the Purcell factor, and discuss their influence on different types of lasers. We obtain the relation between peak emission cross section, radiative lifetime, and emission linewidth. By interpreting spontaneous emission as stimulated emission driven by vacuum fluctuations, we derive the spontaneous-emission rate into a resonator mode and establish physical expressions for the fractions of spontaneous emission and total decay from the upper laser level into this mode. Furthermore, we discuss coupling of the atomic system with the coherent field inside a lasing resonator mode, resulting in the formation of a Mollow triplet, and demonstrate that it leads to a reduction of the spontaneous-emission rate by a factor of 2.
Place, publisher, year, edition, pages
2015. Vol. 21, no 1, 9000216- p.
Lasers, optical resonators, laser modes, luminescence, spontaneous emission
Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-157035DOI: 10.1109/JSTQE.2014.2361783ISI: 000344403400001ScopusID: 2-s2.0-84908431003OAI: oai:DiVA.org:kth-157035DiVA: diva2:768631
QC 201412042014-12-042014-12-042014-12-04Bibliographically approved