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Femtosecond near‐field scanning optical microscopy
Author(s) -
Nechay B. A.,
Siegner U.,
Achermann M.,
MorierGenaud F.,
Schertel A.,
Keller U.
Publication year - 1999
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 - 10.1046/j.1365-2818.1999.00528.x
Subject(s) - femtosecond , materials science , microscopy , optics , optoelectronics , microscope , focused ion beam , ultrashort pulse , optical microscope , near field scanning optical microscope , resolution (logic) , laser , near and far field , scanning probe microscopy , ion , chemistry , physics , scanning electron microscope , organic chemistry , artificial intelligence , computer science
We have developed an instrument for optically measuring carrier dynamics in thin‐film materials with ≈150 nm lateral resolution, ≈250 fs temporal resolution and high sensitivity. This is accomplished by combining an ultrafast pump–probe laser spectroscopic technique with a near‐field scanning optical microscope. A diffraction‐limited pump and near‐field probe configuration is used, with a novel detection system that allows for either two‐colour or degenerate pump and probe photon energies, permitting greater measurement flexibility than that reported in earlier published work. The capabilities of this instrument are proven through near‐field degenerate pump–probe studies of carrier dynamics in GaAs/AlGaAs single quantum well samples locally patterned by focused ion beam (FIB) implantation. We find that lateral carrier diffusion across the nanometre‐scale FIB pattern plays a significant role in the decay of the excited carriers within ≈1 μm of the implanted stripes, an effect which could not have been resolved with a far‐field system.