Mode spacing {open_quotes}anomaly{close_quotes} in InGaN blue lasers

Journal Article · Mon Feb 01 04:00:00 EST 1999 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.123483· OSTI ID:324898

Jiang, H X; Lin, J Y ^[1]

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1. Department of Physics, Kansas State University, Manhattan, Kansas 66506-2601 (United States)

An important experimental observation in InGaN laser diodes (LDs), which is not yet fully understood, is that the measured mode spacing of the lasing spectra could be one order of magnitude larger than that {open_quotes}calculated{close_quotes} from the known cavity length. The aim of this letter is to shed light on the nature of the mode spacing {open_quotes}anomaly{close_quotes} in InGaN LDs. We have derived a formula which accurately determines the mode spacing in InGaN LDs. Our analysis has shown that the discrepancy between the {open_quotes}expected{close_quotes} and observed mode spacing is due to the effect of carrier-induced reduction of the refractive index under lasing conditions and this discrepancy decreases and naturally disappears as the threshold carrier density required for lasing decreases. Since the carrier-induced reduction of the refractive index is expected only from an electron{endash}hole plasma state, our results naturally imply that electron{endash}hole plasma recombination provides the optical gain in InGaN LDs, like in all other conventional III{endash}V semiconductor lasers. The implications of our results on the design of nitride optoelectronic devices are also discussed. {copyright} {ital 1999 American Institute of Physics.}

• OSTI ID: 324898
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 8 Vol. 74; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
CARRIER DENSITY
ELECTRON-HOLE DROPLETS
GAIN
GALLIUM COMPOUNDS
GALLIUM NITRIDES
INDIUM COMPOUNDS
INDIUM NITRIDES
RECOMBINATION
REFRACTIVE INDEX
SEMICONDUCTOR LASERS
SOLID-STATE PLASMA