Beam steering in high-power CW quantum-cascade lasers

We report the light-current (L-I), spectral, and far-field characteristics of quantum cascade lasers (QCLs) with seven different wavelengths in the /spl lambda/=4.3 to 6.3 /spl mu/m range. In continuous-wave (CW) mode, the narrow-stripe (/spl ap/13 /spl mu/m) epitaxial- side-up devices operated at t...

Full description

Saved in:

Bibliographic Details
Published in:	IEEE journal of quantum electronics 2005-06, Vol.41 (6), p.833-841
Main Authors:	Bewley, W.W., Lindle, J.R., Chul Soo Kim, Vurgaftman, I., Meyer, J.R., Evans, A.J., Jae Su Yu, Slivken, S., Razeghi, M.
Format:	Article
Language:	eng
Subjects:	Beam characteristics: profile, intensity, and power spatial pattern formation Beam steering Exact sciences and technology Fundamental areas of phenomenology (including applications) Laser beam steering Laser beams Laser modes Laser optical systems: design and operation Lasers Optical bistability Optical pumping Optics Physics Power generation Quantum cascade lasers Quantum well lasers quantum-well (QW) lasers Semiconductor lasers Semiconductor lasers laser diodes Temperature
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	We report the light-current (L-I), spectral, and far-field characteristics of quantum cascade lasers (QCLs) with seven different wavelengths in the /spl lambda/=4.3 to 6.3 /spl mu/m range. In continuous-wave (CW) mode, the narrow-stripe (/spl ap/13 /spl mu/m) epitaxial- side-up devices operated at temperatures up to 340 K, while at 295 K the CW output power was as high as 640 mW with a wallplug efficiency of 4.5%. All devices with /spl lambda//spl ges/4.7 /spl mu/m achieved room-temperature CW operation, and at T=200 K several produced powers exceeding 1 W with /spl ap/10% wallplug efficiency. The data indicated both spectral and spatial instabilities of the optical modes. For example, minor variations of the current often produced nonmonotonic hopping between spectra with envelopes as narrow as 5-10 nm or as broad as 200-250 nm. Bistable beam steering, by far-field angles of up to /spl plusmn/12/spl deg/ from the facet normal, also occurred, although even in extreme cases the beam quality never became worse than twice the diffraction limit. The observed steering is consistent with a theory for interference and beating between the two lowest order lateral modes. We also describe simulations of a wide-stripe photonic-crystal distributed-feedback QCL, which based on the current material quality is projected to emit multiple watts of CW power into a single-mode beam at T=200 K.
ISSN:	0018-9197 1558-1713