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Title: Coherent beams from high efficiency two-dimensional surface-emitting semiconductor laser arrays

Journal Article · · Applied Physics Letters; (USA)
DOI:https://doi.org/10.1063/1.104468· OSTI ID:5882714
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  1. Sandia National Laboratories, Albuquerque, New Mexico 87185 (US)

We have fabricated and operated large two-dimensional (2D) arrays of phase-locked surface-emitting semiconductor lasers. The arrays were fabricated by reactive ion beam etching of epitaxial Fabry--Perot resonators comprising GaAs/AlGaAs quantum wells surrounded by AlAs-AlGaAs quarter-wave mirrors. Different arrays corresponding to different pixel size (2--5 {mu}m) and spacing (1--2 {mu}m) were produced to investigate evanescent coupling between pixels. The arrays were photopumped so that the array size could be conveniently varied from 1{times}1, 2{times}2,... up to 20{times}20. Except for the 1{times}1 which emits a circular pattern, all arrays exhibit a well-defined four-lobed far-field pattern in agreement with our theoretical analysis of the optical modes which predicts domination by the 2D out-of-phase eigenmode. As a consequence this pattern can be understood with simple Fraunhofer diffraction theory. The angular spread of the lobes, determined by the periodicity of the array elements, is 10{degree} for the array with element size/spacing of 4/1 {mu}m. The widths of the lobes are 6.7{degree} for the 2{times}2 and narrow to 3.2{degree} with increasing number of pixels in the array. The array exhibits a sharp onset for lasing, operation on a single longitudinal mode, and a linewidth which narrows to {similar to}1 A with increasing array size. The differential power efficiency is as high as 70%. These observations provide further impetus and guidance for the development of 2D laser diode arrays.

DOE Contract Number:
AC04-76DP00789
OSTI ID:
5882714
Journal Information:
Applied Physics Letters; (USA), Vol. 58:9; ISSN 0003-6951
Country of Publication:
United States
Language:
English