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Minimum reflection channel in amplifying random media

Seng Fatt Liew, Hui W. Cao

Enhancing light transmission through scattering media is of much interest in many fields. Here, numerical simulations are performed to study the impact of gain on the value of reflection of the minimum reflection channel in a random medium. Surprisingly, in some random configurations, the reflection falls when gain is added even through the intensity inside the medium presumably increases once gain is introduced. This unexpected behavior is explained based on a decomposition of quasinormal modes.Enhancing light transmission through scattering media is of much interest in many fields. Here, numerical simulations are performed to study the impact of gain on the value of reflection of the minimum reflection channel in a random medium. Surprisingly, in some random configurations, the reflection falls when gain is added even through the intensity inside the medium presumably increases once gain is introduced. This unexpected behavior is explained based on a decomposition of quasinormal modes.

arXiv:1508.04792Physical Review BDec 29, 20155 citations

Enhanced internal reflection from an exponential amplifying region

R. F. Cybulski, Mark P. Silverman

The reflectance of a p-polarized wave from an interface between a transparent medium and an amplifying medium with an exponential gain profile is derived. Experimentally determined reflectance curves are in agreement with theory and show amplification in the vicinity of the critical angle.

Optics LettersMar 1, 19835 citations

Description of light amplification on reflection through the complex refraction angle

S. G. Il’ina

Optics and SpectroscopyJan 1, 19880 citations

Excitation-dependent diffuse super-reflection from a random laser

Ravitej Uppu, Sushil A. Mujumdar

Enhancement of the diffusive albedo from a random amplifying medium is discussed. A pump-probe setup is used to study the amplification of the reflected probe pulse light outside the backscattering cone. Strong super-reflection is measured and its dependence on the disorder strength is studied. An optimal disorder strength is observed at high excitation energy wherein the super-reflection is maximal. The origins of this behavior are traced to the interplay between the out-coupling and amplification from a disordered amplifying medium with an inhomogeneous distribution of gain.Enhancement of the diffusive albedo from a random amplifying medium is discussed. A pump-probe setup is used to study the amplification of the reflected probe pulse light outside the backscattering cone. Strong super-reflection is measured and its dependence on the disorder strength is studied. An optimal disorder strength is observed at high excitation energy wherein the super-reflection is maximal. The origins of this behavior are traced to the interplay between the out-coupling and amplification from a disordered amplifying medium with an inhomogeneous distribution of gain.

Physical Review AMay 13, 20150 citations

Photon density wave resonances of amplifying inhomogeneities in a random medium

Lalruatfela Renthlei, S. Anantha Ramakrishna, Harshawardhan Wanare

Amplification in random media is investigated from the perspective of diffuse photon density waves (DPDWs). These exponentially decaying waves, typical in absorbing media, exhibit significantly enhanced propagation characteristics in random amplifying media. Consequently, finite amplifying regions, embedded in an absorbing random medium, exhibit specific resonant features governed by the geometry of the amplifying region. For a spheroidal amplifying region, the scattered waves are dominated by the characteristic multipolar resonances, and the monopolar as well as the dipolar resonances are closely related to random lasing thresholds. The levels of amplification at which the resonance (or lasing) occurs can be used to identify the size, shape, and orientation of the amplifying region. These resonant modes are quite robust and survive, even as the modulation frequency of the DPDW is varied from about 100 MHz to zero, thereby indicating a deeper connection between random lasing path distributions and the appropriate gain profiles resulting in the associated intensity distribution of the DPDW modes.Amplification in random media is investigated from the perspective of diffuse photon density waves (DPDWs). These exponentially decaying waves, typical in absorbing media, exhibit significantly enhanced propagation characteristics in random amplifying media. Consequently, finite amplifying regions, embedded in an absorbing random medium, exhibit specific resonant features governed by the geometry of the amplifying region. For a spheroidal amplifying region, the scattered waves are dominated by the characteristic multipolar resonances, and the monopolar as well as the dipolar resonances are closely related to random lasing thresholds. The levels of amplification at which the resonance (or lasing) occurs can be used to identify the size, shape, and orientation of the amplifying region. These resonant modes are quite robust and survive, even as the modulation frequency of the DPDW is varied from about 100 MHz to zero, thereby indicating a deeper connection between random lasing path distributions and the appropriate gain profiles resulting in the associated intensity distribution of the DPDW modes.

Journal of the Optical Society of America BJun 8, 20171 citation

Coherent Effects in the Multiple Scattering of Light in Random Media

Éric Akkermans, Gilles Montambaux

Springer eBooksJan 1, 20032 citations

Reduced Reflection of Light in Random Amplifying Media

Abstract

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Reduced Reflection of Light in Random Amplifying Media

Abstract

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