Edge-emitting Semiconductor Lasers
Definition: semiconductor lasers emitting light along the plane of the wafer
Alternative term: in-plane lasers
More general term: semiconductor lasers
German: kantenemittierende Halbleiterlaser
How to cite the article; suggest additional literature
Author: Dr. RĂ¼diger Paschotta
Semiconductor lasers can be grouped into two classes:
- Edge-emitting lasers (also called in-plane lasers), where the laser light propagates in a direction along the wafer surface of the semiconductor chip and is reflected or coupled out at a cleaved edge.
- Surface-emitting lasers, where the light propagates in the direction perpendicular to the semiconductor wafer surface.
Edge-emitting lasers are the original and still very widely used form of semiconductor lasers. Their resonator length is typically between a few hundred micrometers and a few millimeters. This is sufficient for reaching a high gain, so that an edge-emitting laser may lase even if the resonator losses are fairly high, e.g. when the end faces (edges) are not coated and there is only the Fresnel reflection of the semiconductor/air interfaces.
Within the edge-emitting laser structure, the laser beam is guided in a waveguide structure. Typically, one uses a double heterostructure, which restricts the generated carriers to a narrow region and at the same time serves as a waveguide for the optical field. This arrangement leads to a low threshold pump power and a high efficiency. Depending on the waveguide properties, particularly its transverse dimensions, it is possible either to obtain an output with high beam quality but limited output power (some hundreds of milliwatts), or (with a broad-area laser diode) an output with high output power (tens of watts or even > 100 W) but with poor beam quality.
Questions and Comments from Users
Here you can submit questions and comments. As far as they get accepted by the author, they will appear above this paragraph together with the author’s answer. The author will decide on acceptance based on certain criteria. Essentially, the issue must be of sufficiently broad interest.
Please do not enter personal data here; we would otherwise delete it soon. (See also our privacy declaration.) If you wish to receive personal feedback or consultancy from the author, please contact him e.g. via e-mail.
By submitting the information, you give your consent to the potential publication of your inputs on our website according to our rules. (If you later retract your consent, we will delete those inputs.) As your inputs are first reviewed by the author, they may be published with some delay.
See also: semiconductor lasers, laser diodes, broad area laser diodes, surface-emitting semiconductor lasers
and other articles in the category lasers
2020-05-14
Are ruby lasers edge emitting?
Answer from the author:
No – this concept has been developed for semiconductor lasers, not for bulk lasers like ruby lasers.