Two-photon single-beam particle trapping of active micro-spheres

摘要

In this paper, we have demonstrated the measurement of the morphology-dependent resonance (MDR) within a laser trapped microsphere excited under two-photon excitation. Both trapping and two-photon excitation are achieved by a single femtosecond pulsed laser beam simultaneously. MDR induced by two-photon excitation has also shown to overcome difficulties in separation of excitation and resonant wavelengths and the inability to confine excitation illumination precisely. A spectrally resolved image demonstrates that this technique provides an alternative imaging mechanism for near-field imaging and mapping surface tomography.