Passive <i>Q</i>-switching of fiber lasers using a broadband liquefying gallium mirror

Petropoulos, P.; Offerhaus, Herman L.; Richardson, David J.; Dhanjal, S.; Zheludev, Nikolay I.

doi:10.1063/1.123200

Cited by 48 publications

(14 citation statements)

References 8 publications

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“…surface enhanced Raman spectroscopy (SERS) [27][28][29] , surface enhanced fluorescence 30,31 , Li-ion batteries 32 , waveguiding 33,34 , optical switching 35,36 , phase-change memories 37 or the development of biosensors for the detection of different diseases 38,39 .…”

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confidence: 99%

Plasmonic coupling in closed-packed ordered gallium nanoparticles

Catalán‐Gómez

Bran

Vázquez

et al. 2020

Sci Rep

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plasmonic gallium (Ga) nanoparticles (nps) are well known to exhibit good performance in numerous applications such as surface enhanced fluorescence and Raman spectroscopy or biosensing. However, to reach the optimal optical performance, the strength of the localized surface plasmon resonances (LSPRs) must be enhanced particularly by suitable narrowing the NP size distribution among other factors. With this purpose, our last work demonstrated the production of hexagonal ordered arrays of Ga NPs by using templates of aluminium (Al) shallow pit arrays, whose LSPRs were observed in the VIS region. The quantitative analysis of the optical properties by spectroscopic ellipsometry confirmed an outstanding improvement of the LSPR intensity and full width at half maximum (FWHM) due to the imposed ordering. Here, by engineering the template dimensions, and therefore by tuning Ga NPs size, we expand the LSPRs of the Ga NPs to cover a wider range of the electromagnetic spectrum from the UV to the IR regions. More interestingly, the factors that cause this optical performance improvement are studied with the universal plasmon ruler equation, supported with discrete dipole approximation simulations. the results allow us to conclude that the plasmonic coupling between nps originated in the ordered systems is the main cause for the optimized optical response. The interaction between metallic nanoparticles (NPs) and the electromagnetic radiation has constituted the driving force for the studies of the light-matter interaction during the last decades 1-3. Due to their free electrons, the metallic NPs are capable to concentrate and amplify the electric near-field in the vicinities of their surfaces. The electron oscillations (plasmons) resonate with light at a certain frequency that is commonly known as the localized surface plasmon resonance (LSPR). This frequency strongly depends on the NP size, shape, contact angle, environment and, especially, on the metal type 4. For instance, in the most studied elements, silver (Ag) and gold (Au), their LSPRs are quite restricted to the visible (VIS) region 5 due to their low losses and interband transitions in the ultraviolet (UV) region. Thus, during the last years, there has been an effort in the scientific community to search for alternative metals 6-8. Among others, liquid gallium (Ga) has emerged as an ideal plasmonic candidate 9,10 since its LSPRs can be tuned from the UV to the infrared (IR) due to the lack of strong interband transitions in this wide region 11 in contrast to other candidates such as Al 12 , Cu 13 or Ni 14. This spectral tunability can be achieved by means of different methods: changing the NP size 15 , contact angle or substrate 16,17 , varying the gallium oxide shell thickness 18 , by hybridization with other plasmonic NPs 19 or by alloying 9,20. In addition to this, the Ga NPs can be grown in a facile, fast and up-scalable method such as Joule-effect thermal evaporation 21,22. This synthesis technique produces self-assembled hemispherical NPs formed by a liquid G...

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confidence: 99%

Plasmonic coupling in closed-packed ordered gallium nanoparticles

Catalán‐Gómez

Bran

Vázquez

et al. 2020

Sci Rep

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“…The generation of nanosecond pulse with high peak power is of importance for many applications such as OTDR, lidar, remote sensing and nonlinear optical processes [1][2][3]. Qswitched fiber lasers have been developed for years to obtain pulsed laser beam with pulsewidth ranging from nanoseconds to microseconds.…”

Section: Introductionmentioning

confidence: 99%

Repetition rate stabilization of the SBS Q-switched fiber laser by external injection

Pan¹,

Li²,

Ye³

et al. 2009

Opt. Express

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Repetition rate fluctuation is one of the main drawbacks of the low-threshold stimulated Brillouin scattering (SBS) Q-switched fiber laser. A method to stabilize the repetition rate is proposed in this paper by injecting a square-wave modulated light. It is measured experimentally that variance of the repetition rate can be improved from ~20% to ~1% of the period. It is also found that effectiveness of the method depends on modulation frequency and duty cycle of the injection. Its working mechanism is analyzed qualitatively.

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“…[18][19][20][21] Particularly important for these applications is the optical reflectivity contrast, expressed as the ratio between the high and low reflectivity values of the two Ga phases. In the visible range this ratio is only (85%)/(53%) for the Ga/glass interface, [1][2][3][4][5][6][7][8][9][10][11][13][14][15][16][17][18][19][20][21] and may be increased by replacing the glass substrate with other dielectric substrates [12] or by coupling the Ga layer to an adjacent optical thin film, such as magnesium fluoride. [22] More recently, the idea of coupling the Ga layer to an optical interference structure has been taken further by proposing to integrate the Ga layer into dedicated optical interference thin film packages [23] in order to design high contrast Ga mirrors.…”

Section: Introductionmentioning

confidence: 97%

“…The significantly different values of the optical constants in the solid and liquid phases of Ga give rise to a significant increase in its light reflectivity. [1][2][3][4][5][6][7][8][9][10][11][12][13] This unusual property serves as a basis for a wide range of optoelectronic applications such as passive Q-switches for lasers, [14,15] all optical switches, [16,17] and phase-change optical memories. [18][19][20][21] Particularly important for these applications is the optical reflectivity contrast, expressed as the ratio between the high and low reflectivity values of the two Ga phases.…”

Section: Introductionmentioning

confidence: 97%

Characterization of the topography and thickness of gallium thin films by scanning tunneling microscopy

Bratfalean

Marconi

Colniță

2016

Instrumentation Science & Technology

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Scanning tunneling microscopy (STM) was employed to characterize the topography of 32 and 4 µm thick gallium films; thicknesses that have not yet been addressed. The STM images revealed submicron grains on both surfaces although a reduced grain density was observed on the thinner film. The granular structure may be explained by a thin gallium oxide layer that acted as an elastic membrane against liquid gallium underneath that expanded during freezing of the sample. We also believe that the same gallium oxide layer is also responsible for an intriguing effect that appears as soon as the tungsten tip lands on the gallium film: the onset of continuous regular z-oscillations of the tip even at rest. This is an effect that we believe has not been previously reported in the literature. We have also demonstrated, for the first time, a new thickness determination method for the gallium film based on an STM image obtained during the solid-to-liquid phase transition.

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Passive Q-switching of fiber lasers using a broadband liquefying gallium mirror

Cited by 48 publications

References 8 publications

Plasmonic coupling in closed-packed ordered gallium nanoparticles

Plasmonic coupling in closed-packed ordered gallium nanoparticles

Repetition rate stabilization of the SBS Q-switched fiber laser by external injection

Characterization of the topography and thickness of gallium thin films by scanning tunneling microscopy

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