Tapping-mode tuning-fork near-field scanning optical microscopy of low power semiconductor lasers |
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Authors: | N H Lu W C Lin† & D P Tsai† |
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Affiliation: | Department of Electronic Engineering, Sze-hai Institute of Technology and Commerce, Tuchen Taipei County, 236 Taiwan, Republic of China;Department of Physics, National Taiwan University, No.1, Sec. 4, Roosevelt Road, Taipei, 10617 Taiwan, Republic of China |
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Abstract: | The newly developed inverted tapping-mode tuning-fork near-field scanning optical microscopy (TMTF-NSOM) is used to study the local near-field optical properties of strained AlGaInP/Ga0.4In0.6P low power visible multiquantum-well laser diodes. In contrast to shear-force mode NSOM, TMTF-NSOM provides the function to acquire the evanescent wave intensity ratio | I (2ω)|/| I (ω)| image, from which the evanescent wave decay coefficient q can be evaluated for a known tapping amplitude. Moreover, we probe the near-field stimulated emission spectrum, which gives the free-space laser light wavelength λo and the index of refraction n r of the laser diode resonant cavity. Once q , λo, and n r are all measured, we can determine the angle of incidence θo of the dominant totally internally reflected waves incident on the front mirror facet of the resonator. Determination of such an angle is very important in modelling the stability of the laser diode resonator. |
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Keywords: | Evanescent waves near-field scanning optical microscopy semiconductor laser tapping-mode |
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