Disorder-induced cavities, resonances, and lasing in randomly layered media

Bliokh, Yu. P.; Chaikina, E. I.; Lizárraga, N.; Mendez, Eugenio Rafael Mendez; Freilikher, V.; Nori, Franco

doi:10.1103/physrevb.86.054204

Cited by 19 publications

(19 citation statements)

References 41 publications

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“…In recent years they have attracted a great deal of attention, mainly due to the versatility stemming from cavity-less geometries and the ease of realization [1][2][3][4][5][6][7][8][9]. In liquid crystals, suitable dopants can provide the gain action through optical pumping, while optical birefringence in conjunction with intense fluctuations of the dielectric tensor yield the required recurrent multiple scattering for random resonances to occur [10][11][12][13][14][15][16][17].…”

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confidence: 99%

Soliton-assisted random lasing in optically-pumped liquid crystals

Perumbilavil

Piccardi

Buchnev

et al. 2016

Applied Physics Letters

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We demonstrate a novel random laser configuration by exploiting the coexistence of optical gain and light self-localization in a reorientational nonlinear medium. A spatial soliton launched by a near-infrared beam in dye-doped nematic liquid crystals enhances and confines stimulated emission of visible light in the optically-pumped gain-medium, yielding random lasing with enhanced features.In random lasers, a disordered distribution of scattering centers provides the required feedback for oscillations in optically amplifying media. In recent years they have attracted a great deal of attention, mainly due to the versatility stemming from cavity-less geometries and the ease of realization [1][2][3][4][5][6][7][8][9]. In liquid crystals, suitable dopants can provide the gain action through optical pumping, while optical birefringence in conjunction with intense fluctuations of the dielectric tensor yield the required recurrent multiple scattering for random resonances to occur [10][11][12][13][14][15][16][17]. In the nematic phase, moreover, liquid crystals are positive uniaxial materials subject to optic axis reorientation under the action of electric fields, either at low or optical frequencies [18]. The latter response provides a low-power mechanism for nonlinear optics [19] and light localization into self-confined lightbeams, the so-called "nematicons" [20]. Nematicons are bright spatial solitons (solitary waves) which are stable in two transverse dimensions due to the nonlocal response associated with the elastic intermolecular links in the liquid state [21,22]; they support graded-index waveguides able to confine additional (incoherent) signals/beams of different wavelengths as well as powers and profiles [23][24][25][26][27][28][29][30], are robust against refractive index perturbations [31-35] and collisional interactions [36][37][38]. Aided by nematicons, reorientational and electronic nonlinear responses, characterized by distinct time-and power-scales, can synergystically be combined [39,40]. Owing to their large numerical aperture [41], nematicon waveguides solitons have also been employed in experiments involving incoherent light generation by fluorescence [42] or amplified spontaneous emission [43], offering a means to better collect and couple the emitted light into optical fibers.In this Letter we demonstrate a novel example of synergy between diverse nonlinear responses: the combination of spatial solitons and random lasing into a "nematicon random laser", whereby a low-power self-confined beam provides a guided-wave landscape for the stimu- * assanto@uniroma3.it lated emission induced by collinear optical pumping of dye-doped nematic liquid crystals (NLC).Several benefits can be expected from adopting such light-induced guided-wave configuration for random lasing. At variance with standard thin film geometries, the thick NLC cell provides an extended volume where optical pumping can produce fluorescence and, in turn, stimulated emission and lasing action via random scattering and feedback. The la...

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confidence: 99%

Soliton-assisted random lasing in optically-pumped liquid crystals

Perumbilavil

Piccardi

Buchnev

et al. 2016

Applied Physics Letters

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“…It is also possible to artificially introduce randomness within the fiber medium in a controlled fashion, which can in turn provide additional flexibility in tailoring the spectral properties of random lasers. For example, it is known that gratings having randomly distributed phase shifts can exhibit extremely high-Q resonances [97,98]. In [97], light propagation and localization in randomly spaced fiber gratings in a SMF were studied both theoretically and experimentally.…”

Section: Spectral Properties Of Random Fiber Lasers Of Other Typesmentioning

confidence: 99%

“…The light transmission was measured after each additional grating fabrication and an exponential decay characteristic for the localization theory was demonstrated. In [98], disorder-induced resonances in randomly layered structures have been studied theoretically and experimentally. An algorithm was proposed and developed for the detection and characterization of the effective cavities that give rise to randomnessinduced resonances.…”

Section: Spectral Properties Of Random Fiber Lasers Of Other Typesmentioning

confidence: 99%

“…An algorithm was proposed and developed for the detection and characterization of the effective cavities that give rise to randomnessinduced resonances. It was shown in [98] that in an active, amplifying medium, some of the cavities may host lasing modes and the ensemble of lasing cavities may behave as DFB lasers. Artificially introduced randomly located resonant Bragg reflectors (periodic gratings) in a fiber laser system led to typical random lasing in which the resonances revealed themselves through the peaks in the emission spectrum.…”

Section: Spectral Properties Of Random Fiber Lasers Of Other Typesmentioning

confidence: 99%

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Recent advances in fundamentals and applications of random fiber lasers

et al. 2015

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Doc. ID 239686)Random fiber lasers blend together attractive features of traditional random lasers, such as low cost and simplicity of fabrication, with high-performance characteristics of conventional fiber lasers, such as good directionality and high efficiency. Low coherence of random lasers is important for speckle-free imaging applications. The random fiber laser with distributed feedback proposed in 2010 led to a quickly developing class of light sources that utilize inherent optical fiber disorder in the form of the Rayleigh scattering and distributed Raman gain. The random fiber laser is an interesting and practically important example of a photonic device based on exploitation of optical medium disorder. We provide an overview of recent advances in this field, including high-power and high-efficiency generation, spectral and statistical properties of random fiber lasers, nonlinear kinetic theory of such systems, and emerging applications in telecommunications and distributed sensing.

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“…The great potential of such algorithms for a host of practical applications is obvious. This is why the relation between transmission resonances and QNMs have recently attracted particular attention of both the physical [12,[24][25][26][27][28] and mathematical communities [1].It is now universally accepted that in open systems (e.g., quantum potential wells, optical cavities, or microwave resonators) each maximum in the transmission coefficient (i.e., transmission resonance) is associated with a QNM, so that the resonant frequency is close to the real part of the corresponding eigenvalue. QNMs and TRs are often considered identical.…”

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confidence: 99%

Disorder-induced mutation of quasi-normal modes in 1D open systems

Bliokh

Freilikher

Nori

2016

2016 URSI International Symposium on Electromagnetic Theory (EMTS)

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We study the relation between quasi-normal modes (QNMs) and transmission resonances (TRs) in one-dimensional (1D) disordered systems. We show for the first time that while each maximum in the transmission coefficient is always related to a QNM, the reverse statement is not necessarily correct. There exists an intermediate state, where only part of the QNMs are localized and these QNMs provide a resonant transmission. The rest of the solutions of the eigenvalue problem (denoted as strange quasi-modes) are never found in regular open cavities and resonators, and arise exclusively due to random scatterings. Although these strange QNMs belong to a discrete spectrum, they are not localized and not associated with any anomalies in the transmission. The ratio of the number of the normal QNMs to the total number of QNMs is independent of the type of disorder, and deviates only slightly from the constant 2/5 in rather wide ranges of the strength of a single scattering and the length of the random sample.Wave processes in open systems can be described in terms of quasi-normal modes (QNMs), which are a generalization of the notion of normal modes for closed systems, to open structures, [1][2][3][4][5][6][7][8][9]. The corresponding eigenfrequencies are complex, so that the imaginary parts characterize the lifetime of the quasi-normal states. Regarding the transmission of radiation through random media, it is more appropriate to use an alternative approach based on transmission resonances (TR): open channels, through which the radiation transmits with high efficiency [3,[10][11][12][13][14][15][16][17][18][19][20][21][22].Recently, physicists came to realize that focusing radiation into such channels could not only enhance the total intensity transmitted through strongly-scattering media, but also: significantly improve images blurred by random scattering, facilitate the detection and location of objects, provide optical tomography at very large depths, etc. [13,17,18,20,23]. To efficiently excite transmission resonances, it is preferable to treat them as superpositions of QNMs, with which the incident signal can be coupled by a properly-shaped wavefront [13,14]. The great potential of such algorithms for a host of practical applications is obvious. This is why the relation between transmission resonances and QNMs have recently attracted particular attention of both the physical [12,[24][25][26][27][28] and mathematical communities [1].It is now universally accepted that in open systems (e.g., quantum potential wells, optical cavities, or microwave resonators) each maximum in the transmission coefficient (i.e., transmission resonance) is associated with a QNM, so that the resonant frequency is close to the real part of the corresponding eigenvalue. QNMs and TRs are often considered identical. For example, the solutions of the eigenvalue problem (with no incoming waves), which in physics are unambiguously called QNMs, in the mathematical community dealing with the scattering inverse problem, are termed transmission eigenvalu...

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Disorder-induced cavities, resonances, and lasing in randomly layered media

Cited by 19 publications

References 41 publications

Soliton-assisted random lasing in optically-pumped liquid crystals

Soliton-assisted random lasing in optically-pumped liquid crystals

Recent advances in fundamentals and applications of random fiber lasers

Disorder-induced mutation of quasi-normal modes in 1D open systems

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