| 研究実績の概要 |
We have fabricated high-order modes(HOM) optical nanofibers with the highest possible transmission and taking ~ 100 mW in the vacuum chamber,which is a significant step towards atom trapping near fibre surface. HOM nanofibers have been installed into the vacuum system and fluorescence photons from cold atoms in the MOT were directly collected by the fibre output ports. Each eigenmodes of the LP11 group of this nanofiber have been excited and separated by injecting the vector beams in free space. In order to increase the duration time of atoms in the evanescent field of fibre, we have realized effective temperature of atoms in the MOT down to tens of uK by using polarization gradient cooling. We have developed LabVIEW programmes to control the whole experiment processing.
The interaction strength for different modes have been obtained by measuring the atomic absorption spectra of the guided resonant beam. This make a first step towards the transfer of orbital angular momentum (OAM) in atom-fibre system based on four wave mixing(FWM). We have built the laser systems which will be used as pumping beams in four wave mixing process. The wavelength of lasers has been locked to atomic transition line by using saturated absorption spectroscopy or two photon absorption spectroscopy. The signal of FWM have been obtained in free space but we have not implemented in atom-fibre system.
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