The authors demonstrate more than 9 nm tunability of the whispering gallery modes ͑WGMs͒ of rhodamine B doped water microdroplets resting on a superhydrophobic surface. Tunability was achieved by controlling the size of the microdroplets in a current controlled mini humidity chamber. WGMs were observed with quality factors of more than 8000 when kept stable. The sensitivity of the resonances to the size and shape of the microdroplet reveals opportunities for the use of this technique as a probe to characterize superhydrophobic surfaces and investigate liquid-solid surfaces.

We report laser emission from single, stationary, Rhodamine B-doped glycerol/water microdroplets located on a superhydrophobic surface. In the experiments, a pulsed, frequency-doubled Nd:YAG laser operating at 532 nm was used as the excitation source. The microdroplets ranged in diameter from a few to 20 µm. Lasing was achieved in the red-shifted portion of the dye emission spectrum with threshold fluences as low as 750 J/cm 2 .Photobleaching was observed when the microdroplets were pumped above threshold. In certain cases, multimode lasing was also observed and attributed to the simultaneous lasing of two modes belonging to different sets of whispering gallery modes. a) akiraz@ku.edu.tr b) asennar@ku.edu.tr

Dundar, M.A.; Ryckebosch, E.C.I.; Nötzel, R.; Karouta, F.; van IJzendoorn, L.J.; van der Heijden, R.W. Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

Using a micromanipulation technique, a planar photonic crystal nanocavity made from a thin semiconductor membrane is released from the host semiconductor and attached to the end facet of a standard single-mode optical fiber. The cavity spectrum can be read out through the fiber by detecting the photoluminescence of embedded quantum dots. The modified fiber end serves as a fiber-optic refractive index sensor.

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