Whispering Gallery Mode Emission of a Cylindrical Droplet Laser

Mitsunori Saito, Takuya Hashimoto


A cylindrical droplet laser was fabricated in a silicone rubber by using a polyethylene-glycol solution of rhodamine 6G. The silicone rubber provided a simple molding process for enclosing the droplet, since silicone oil solidified at room temperature by only adding a curing agent. Polyethylene glycol dissolved a large amount of dye molecules, yielding a fluorescent solution whose refractive index (1.46) was higher than that of the silicone rubber (1.40). Consequently, some fluorescence rays circulated in the cylindrical droplet owing to the total internal reflection on the side surface (the whispering gallery mode). Other fluorescence rays made round trips in the radial or axial directions of the cylindrical droplet (the radial and axial modes) being reflected at the side or bottom surfaces. When the droplet was excited by a green laser pulse (wavelength: 527 nm, pulse duration: 10 ns), these emission modes competed with one another to induce a stimulated emission. In a droplet with 2.0 mm diameter and 1.4 mm height, the whispering gallery mode conquered the other emission modes, exhibiting a non-linear peak growth and a peak-width narrowing when the excitation energy exceeded 20 μJ (the threshold energy of the stimulated emission).


  1. Matsko, A. B., ed., 2009. Practical Applications of Microresonators in Optics and Photonics, CRC Press. Boca Raton, Florida.
  2. Tzeng, H.-M., Wall, K. F., Long, M. B., Chang, R. K., 1984. Laser emission from individual droplets at wavelengths corresponding to morphology-dependent resonances. Opt. Lett. 9(11). p. 499-501.
  3. Campillo, A. J., Eversole, J. D., Lin, H.-B., 1991. Cavity quantum electrodynamic enhancement of stimulated emission in microdroplets. Phys. Rev. Lett. 67(4). p. 437-440.
  4. Biswas, A., Latifi, H., Armstrong, R. L., Pinnick, R. G., 1989. Time-resolved spectroscopy of laser emission from dye-doped droplets. Opt. Lett. 14(4). p. 214-216.
  5. Sasaki, K., Fujiwara, H., Masuhara, H., 1997. Optical manipulation of a lasing microparticle and its application to near-infrared microspectroscopy. J. Vac. Sci. Technol. B, 15(6). p. 2786-2790.
  6. Arnold, S., Khoshsima, M., Teraoka, I., Holler, S., Vollmer, F., 2003. Shift of whispering-gallery modes in microspheres by protein adsorption. Opt. Lett. 28(4). p. 272-274.
  7. Hara, Y., Mukaiyama, T., Takeda, K., Kuwata-Gonokami, M., 2005. Heavy photon states in photonic chains of resonantly coupled cavities with supermonodispersive microspheres. Phys. Rev. Lett. 94(20). p. 203905-1-4.
  8. Barnes, M. D., Ng, K. C., Whitten, W. B., Ramsey, J. M., 1993. Detection of single rhodamine 6G molecules in levitated microdroplets. Anal. Chem. 65(17). p. 2360- 2365.
  9. Kaqradag, Y., Aas, M., Jonáš, A., Anand, S., McGloin, D., Kiraz, A., 2013. Dye lasing in optically manipulated liquid aerosols. Opt. Lett. 38(10). p. 1669-1671.
  10. Tanyeri, M., Perron, R., Kennedy, I. M., 2007. Lasing droplets in a microfabricated channel. Opt. Lett. 32(17). p. 2529-2531.
  11. Saito, M., Shimatani, H., Naruhashi, H., 2008. Tunable whispering gallery mode emission from a microdroplet in elastomer. Opt. Express, 16(16). p. 11915-11919.
  12. Saito, M., Koyama, K., 2012. Spatial and polarization characteristics of a deformed droplet laser. J. Opt. 14(6). p. 065002-1-6.
  13. Humar, H., Ravnik, M., Pajk, S., Muševic, I., 2009. Electrically tunable liquid crystal optical microresonators. Nature Photon. 3. p. 595-600.
  14. Schwefel, H. G. L., Rex, N. B., Tureci, H. E., Chang, R. K., Stone, A. D., Ben-Messaoud, T., Zyss, J., 2004. Dramatic shape sensitivity of directional emission patterns from similarly deformed cylindrical polymer lasers. J. Opt. Soc. Am. B, 21(6). p. 923-934.
  15. Kawada Co., Ltd. (Japan), 2012. What's Nanoblock? http://www.diablock.co.jp/kawada/en/nanoblock/about.
  16. Saito, M., Ishiguro, H., 2006. Anisotropic fluorescence emission of a dye-doped fibre ring that is pumped by a ring laser beam. J. Opt. A: Pure Appl. Opt. 8(1). p. 208-213.
  17. Saito, M., Nishimura, T., Hamazaki, T., 2015. Faderesistant photochromic reactions in a self-healable polymer. Opt. Express, 23(20). p. 25523-25531.
  18. Saito, M., Nishimura, Y., 2016. Bistable random laser that uses a phase transition of polyethylene glycol. Appl. Phys. Lett. 108(13). p. 131107-1-4.

Paper Citation

in Harvard Style

Saito M. and Hashimoto T. (2017). Whispering Gallery Mode Emission of a Cylindrical Droplet Laser . In Proceedings of the 5th International Conference on Photonics, Optics and Laser Technology - Volume 1: PHOTOPTICS, ISBN 978-989-758-223-3, pages 32-38. DOI: 10.5220/0006089800320038

in Bibtex Style

author={Mitsunori Saito and Takuya Hashimoto},
title={Whispering Gallery Mode Emission of a Cylindrical Droplet Laser},
booktitle={Proceedings of the 5th International Conference on Photonics, Optics and Laser Technology - Volume 1: PHOTOPTICS,},

in EndNote Style

JO - Proceedings of the 5th International Conference on Photonics, Optics and Laser Technology - Volume 1: PHOTOPTICS,
TI - Whispering Gallery Mode Emission of a Cylindrical Droplet Laser
SN - 978-989-758-223-3
AU - Saito M.
AU - Hashimoto T.
PY - 2017
SP - 32
EP - 38
DO - 10.5220/0006089800320038