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Experimental research on the performance of a very‐small‐aperture laser
Author(s) -
HONGFENG GAI,
WANG JIA,
TIAN QIAN,
XIA WEI,
XIANGANG XU,
HAN SHUO,
HAO ZHIBIAO
Publication year - 2008
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.2008.01934.x
Subject(s) - aperture (computer memory) , optics , materials science , beam divergence , facet (psychology) , diffraction , laser , angular aperture , near and far field , laser diode , lasing threshold , diode , field (mathematics) , optoelectronics , physics , lens (geology) , focal length , laser beams , laser beam quality , mathematics , psychology , social psychology , personality , acoustics , pure mathematics , big five personality traits
Summary Very‐small‐aperture lasers (VSALs) with different aperture shapes are fabricated. Their far‐field and near‐field performance is analyzed experimentally. The far‐field performance, including the threshold current, the slope efficiency, the lasing ability and the linear frequency modulation property, is found to be influenced by the front facet reflectivity. A new factor is tentatively proposed to analyze the lasing abilities of VSALs with different aperture shapes. This factor can diminish the discrepancies among the same type laser diodes. The near‐field performance focusses on the confinement effect of the VSAL aperture. A near‐field scanning optical microscopy is used to measure the near‐field intensity distribution from a VSAL. The experimental results indicate that the near‐field performance is affected by the aperture shape. A 100‐nm C‐aperture is proved to be superior to a 100 × 300 nm 2 rectangular aperture on both power throughput and peak intensity. These two apertures are fabricated on the same VSAL facet for the fairness of comparison. An optical spot beyond the diffraction limit is also obtained by fabricating a 70‐nm C‐aperture on a VSAL facet.