Ultrafast measurement in GaAs thin films using NSOM

Ultramicroscopy

Volumn 71, Issue 1-4, 1998, Pages 213-223

  Smith, Steve ^a   Holme, Niels Christian Roemer ^a   Orr, Brad ^a   Kopelman, Raoul ^a   Norris, Ted ^a  

^a UNIVERSITY OF MICHIGAN   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

COOLING; EPITAXIAL GROWTH; MICROSTRUCTURE; RELAXATION PROCESSES; SEMICONDUCTING GALLIUM ARSENIDE; SPECTROSCOPY; THIN FILMS;

EQUAL PULSE CORRELATION TECHNIQUE; NEAR FIELD SCANNING OPTICAL MICROSCOPY; ULTRAFAST MEASUREMENT;

OPTICAL MICROSCOPY;

ARTICLE; CORRELATION FUNCTION; FILM; IMAGE RECONSTRUCTION; IMAGING; SCANNING NEAR FIELD OPTICAL MICROSCOPY;

EID: 0032033220     PISSN: 03043991     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0304-3991(97)00062-4     Document Type: Article

References (18)

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5. We have previously shown that using gratings, the material dispersion in the fiber can be compensated and the pulse width preserved through the NSOM tip: S. Smith et al., Ultramicroscopy 57 (2) (1995) 173.
6. Because the pump and probe are equal in intensity, the probe pulse has an identical effect on the absorption seen by the pump pulse, with the exception that it is time reversed. Therefore, the labels "pump" and "probe" simply identify the time ordering at a given delay. Strictly speaking, the pump and probe are identical.
7. Treacy E.B. IEEE J. Quantum Electron. QE-5(9):1969;454.
8. -3..
9. -4 have been measured with tip diameters ranging form 300 nm down to 130 nm, with commensurately lower signal-to-noise ratios for smaller tips. We have found that tip diameters of at least ≈200 nm give signal-to-noise ratios that allow two-dimensional imaging over practical time scales. The images presented here were acquired over an 8 h time span, ≈2 h at each time delay, using an ≈250 nm diameter tip.
10. -3.
11. Jackson J.D. Classical Electrodynamics. 1962;Wiley, New York.
12. J.B. Stark et al., paper QTuJ1, CLEO, 1995.
13. Levy J., Niktin V., Kikkawa J.M., Awschalom D.D., Samarth N. J. Appl. Phys. 79(8):1996;6095.
14. tip≈200 nm or larger must be used with the NSOM EPC method to achieve reasonable signal-to-noise levels. However, in order to compare with a linear technique (fluoresecence NSOM of Rhodamine 6G) a smaller tip was used to ensure that the propagating modes at the shorter wavelength required to excite Rhodamine (λ=514 nm) would not dominate the measurement. A lower signal-to-nosie ratio was tolerated in the NSOM EPC measurement and the data shown has been smoothed.
15. Jasprit Singh Semiconductor Optoelectronics: Physics and Technology. 1995;McGraw-Hill, New York.
16. 3 attributed to LO phonon emission (typically 150-300 fs at ΔE=130 meV).
17. S. Smith et al., Paper QTuJ5, QELS, 1995.
18. S. Smith, PhD Thesis, Univ. of Michigan, 1996.