Browsing by Author "He, T."

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    Multicolor lasing prints
    (American Institute of Physics Inc., 2015) Ta V.D.; Yang, S.; Wang, Y.; Gao, Y.; He, T.; Chen, R.; Demir, Hilmi Volkan; Sun H.
    This work demonstrates mass production of printable multi-color lasing microarrays based on uniform hemispherical microcavities on a distributed Bragg reflector using inkjet technique. By embedding two different organic dyes into these prints, optically pumped whispering gallery mode microlasers with lasing wavelengths in green and red spectral ranges are realized. The spectral linewidth of the lasing modes is found as narrow as 0.11 nm. Interestingly, dual-color lasing emission in the ranges of 515-535 nm and 585-605 nm is simultaneously achieved by using two different dyes with certain ratios. Spectroscopic measurements elucidate the energy transfer process from the green dye (donor) to the red one (acceptor) with an energy transfer efficiency up to 80% in which the nonradiative Förster resonance energy transfer dominates. As such, the acceptor lasing in the presence of donor exhibits a significantly lower (∼2.5-fold) threshold compared with that of the pure acceptor lasing with the same concentration. © 2015 AIP Publishing LLC.
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    Reconfigurable Liquid Whispering Gallery Mode Microlasers
    (Nature Publishing Group, 2016) Yang, S.; Ta, V. D.; Wang, Y.; Chen, R.; He, T.; Demir, Hilmi Volkan; Sun, H.
    Engineering photonic devices from liquid has been emerging as a fascinating research avenue. Reconfigurably tuning liquid optical micro-devices are highly desirable but remain extremely challenging because of the fluidic nature. In this article we demonstrate an all-liquid tunable whispering gallery mode microlaser floating on a liquid surface fabricated by using inkjet print technique. We show that the cavity resonance of such liquid lasers could be reconfigurably manipulated by surface tension alteration originated from the tiny concentration change of the surfactant in the supporting liquid. As such, remarkable sensing of water-soluble organic compounds with a sensitivity of free spectral range as high as 19.85 THz/(mol · mL-1) and the detectivity limit around 5.56 × 10-3 mol · mL-1 is achieved. Our work provides not only a novel approach to effectively tuning a laser resonator but also new insight into potential applications in biological, chemical and environmental sensing.