Threshold property of whispering-gallery-mode fiber lasers pumped by evanescent waves

Zhang, Yuanxian; Pu, Ximing; Zhu, Kun; Li, Feng

doi:10.1364/josab.28.002048

Cited by 26 publications

(22 citation statements)

References 13 publications

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“…However, the lasing threshold is a comprehensive result of Q factor, materials, as well as pumping, so it varies for different WGM microlaser configurations and pumping schemes. Theoretical calculations of lasing thresholds are usually based on the critical point of optical gain equal to loss, which is the definition of threshold, to figure out the expression for particular structures . In general, the relatively high Q factor and large energy density enable WGM microlasers to have ultra‐low lasing thresholds, on the level of μJ and nJ …”

Section: Characterization Of Wgm Microcavities and Microlasersmentioning

confidence: 99%

Advances and Prospects for Whispering Gallery Mode Microcavities

Yang

Wang

Sun

2015

Advanced Optical Materials

300

183

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Microlasers have experienced tremendous development in the past decade and become an essential part in laser evolution, as miniature lasers provide strong optical confinement and feature greatly enhanced light–matter interactions. Among all the configurations, whispering gallery mode (WGM) microcavities and microlasers exhibit outstanding optical performances with high quality factors and small mode volumes, thus ensuring low lasing thresholds. In addition, some unique properties inherent to WGM cavities, like bi‐directional propagation and an evanescent field that spans several hundred nanometers across the boundary, can be exploited for novel applications. Therefore, designing and engineering innovative WGM microcavities and microlasers has attracted increasing research interest. The fundamentals and characteristics of WGM are introduced here, and then the developments and current status of WGM microcavities and microlasers are reviewed in terms of the evolution of fabrication techniques and built‐up materials. In particular, the melting of glassy materials in early studies, top‐down and bottom‐up approaches with semiconductors, coating structures, as well as flexible, soft microresonators in recent years are presented. Finally, the application prospects of microlasers including the wavelength manipulation, sensing and microresonator coupling, are discussed.

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Section: Characterization Of Wgm Microcavities and Microlasersmentioning

confidence: 99%

Advances and Prospects for Whispering Gallery Mode Microcavities

Yang

Wang

Sun

2015

Advanced Optical Materials

300

183

View full text Add to dashboard Cite

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“…The detail of the experimental setup is described in Ref. [15]. Here, RhB is employed as the gain medium, and the glycerol aqueous solution (RI n 2 = 1.415, dye concentration = 0.5 mM) is used as the solvent.…”

Section: Methodsmentioning

confidence: 99%

“…Based on the asymptotic formula (Eq. (1)) [15] for the resonant positions of WGMs in a ring resonator, the modes in the lasing spectra in Fig. 3(c) have been assigned by the radial mode order (l) and the azimuth mode number (n), where a l is the roots of Airy function, λ n l is the resonant wavelength which is determined by the dye concentration and the RI of the dye solution for a fixed ring resonator diameter.…”

Section: Methodsmentioning

confidence: 99%

“…Under the condition of evanescent wave pumping, when a pump beam experiences a TIR at the surface of the fiber and the dye solution, the evanescent wave of the pump light excites the dye molecules and generates an optical gain around the fiber surface within the WGM evanescent wave. The total lasing gain (G) can be expressed as [15]…”

Section: Theoretical Analysismentioning

confidence: 99%

“…The conventional EPGCFL is formed by inserting a fiber into a capillary tube filled with a low refractive index (RI) gain medium [15]. Although considerable progress has been made in both experimental and theoretical aspects of the EPGCFL [10], [15], [16], to date it has two major drawbacks: (i) the fiber is always suspended in the gain medium, which is difficult to keep mechanical stability of the ring resonator for manual manipulation so that it is challenging to mount the fiber on a chip; (ii) to avoid photobleaching, dye solution should be refreshed frequently which consumes large amount of dye solutions. In the present paper, we address these issues by integrating a segment optical fiber in a polydimethylsiloxane (PDMS) substrate microfluidic channel, in which the lower RI gain medium is passed through the microfluidic channel.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Study on Lasing Threshold Properties of Rhodamine B in Glycerol Aqueous Solution

Zhang

et al. 2019

IEEE Photonics J.

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An optical fiber is integrated in a polydimethylsiloxane substrate microfluidic channel. The laser gain medium consists of glycerol aqueous solution doped with rhodamine B (RhB) molecules, which has a lower refractive index (RI) than that of the optical fiber. The circular cross section of the optical fiber forms an optofluidic ring resonator and hosts highquality (Q) whispering gallery modes (WGMs). Optically pumped along the fiber axis, lasing threshold properties of the RhB glycerol aqueous solution have been investigated. With the increase of both RhB dye concentration and the RI of the glycerol aqueous solution, the recorded lasing threshold decreases at first and then increases. Therefore, there is a best dye concentration as well as a best RI of the dye solution that corresponds to the lowest lasing threshold. Additionally, lasing threshold for the mixed solution of ethanol and ethylene glycol doped with RhB molecules is also demonstrated, which is much higher than that of the glycerol aqueous solution for the same dye concentration and the same RI of the dye solution. Based on evanescent wave pumped and gain coupled WGM lasing theory, we compute the lasing threshold varied with the dye concentration and the RI of the dye solution. The simulation results agree well with the experimental data.

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Spectral behaviors of evanescent-wave-coupled gain lasing from dielectric-coated cylindrical microcavities

Moon

2021

J. Korean Phys. Soc.

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The spectral behavior of evanescent-wave-pumped and gain-coupled lasing was investigated in a dielectric-coated optical fiber surrounded by a dye-doped liquid. As the coating thickness increases, the lasing spectrum exhibits a blue shift due to a decrease in the number of the dye molecules in the evanescent field region of the whispering gallery mode. For comparison, lasing spectra of bare fibers with different dye concentrations were also measured. A simple model for evanescent-wave gain-coupled lasing in a coated cavity is proposed to explain the observed shifting behaviour.

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Threshold property of whispering-gallery-mode fiber lasers pumped by evanescent waves

Cited by 26 publications

References 13 publications

Advances and Prospects for Whispering Gallery Mode Microcavities

Advances and Prospects for Whispering Gallery Mode Microcavities

The Study on Lasing Threshold Properties of Rhodamine B in Glycerol Aqueous Solution

Spectral behaviors of evanescent-wave-coupled gain lasing from dielectric-coated cylindrical microcavities

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