The linewidth enhancement factor of intersubband lasers: From a two-level limit to gain without inversion conditions

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

The linewidth enhancement (α factor) due to fluctuations in the refractive index induced by carrier fluctuations of intersubband lasers was initially expected to be zero. However, values ranging from -0.5 to 3 have been found experimentally. This paper resolves this controversy showing that counter rotating terms, usually ignored in simulations, are the actual fundamental origin of nonzero α at peak gain even without the inclusion of nonparabolicity and manybody effects, which are however needed to explain negative values. For laser without inversion conditions, significant as a potential out of the box solution for the elusive room temperature operation of terahertz lasers, α is found to be larger, but still at the same order of magnitude of conventional inverted medium lasers, thus ensuring their applicability to a huge number of spectroscopic applications that require sharp laser linewidths.

Original languageBritish English
Article number222102
JournalApplied Physics Letters
Volume109
Issue number22
DOIs
StatePublished - 28 Nov 2016

Fingerprint

Dive into the research topics of 'The linewidth enhancement factor of intersubband lasers: From a two-level limit to gain without inversion conditions'. Together they form a unique fingerprint.

Cite this