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https://hdl.handle.net/10356/97872
Title: | Single-mode narrow beam divergence surface-emitting concentric-circular-grating terahertz quantum cascade lasers | Authors: | Khanna, Suraj P. Liang, Guozhen Liang, Houkun Zhang, Ying Li, Lianhe Davies, A. Giles Linfield, Edmund Lim, Dau Fatt Tan, Chuan Seng Yu, Siu Fung Liu, Hui Chun Wang, Qi Jie |
Issue Date: | 2012 | Source: | Liang, G., Liang, H., Zhang, Y., Khanna, S. P., Li, L., Davies, A. G., et al. (2012). Single-mode narrow beam divergence surface-emitting concentric-circular-grating terahertz quantum cascade lasers. 2012 Photonics Global Conference (PGC). | Conference: | Photonics Global Conference (2012 : Singapore) | Abstract: | Single-mode surface-emitting terahertz quantum cascade lasers with second-order concentric-circular-gratings are firstly demonstrated. The gratings are designed for single-mode operation and surface emission for efficient and directional optical power out-coupling. The first structure exhibits single-mode operation over the entire dynamic range with a side-mode-suppression-ratio of around 30 dB, and a six-fold rotationally symmetric far-field pattern, while a modified structure demonstrates single-mode operation with an improved beam divergence, whose far-field patteren consists of two lobes, each of which has a beam divergence within 13.5°×7° (full-width at half-maximum, FWHM). In addition, the devices show a peak output power approximately three times higher than in conventional ridge-waveguide lasers of similar size, whilst maintaining similar threshold current densities and maximum operating temperatures. | URI: | https://hdl.handle.net/10356/97872 http://hdl.handle.net/10220/12199 |
DOI: | 10.1109/PGC.2012.6458023 | Schools: | School of Electrical and Electronic Engineering School of Physical and Mathematical Sciences |
Organisations: | A*STAR SIMTech | Research Centres: | Research Techno Plaza | Rights: | © 2012 IEEE. | Fulltext Permission: | none | Fulltext Availability: | No Fulltext |
Appears in Collections: | EEE Conference Papers |
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