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Genack AZ, Huang Y, Maor A, Shi Z. Velocities of transmission eigenchannels and diffusion. Nat Commun 2024; 15:2606. [PMID: 38521807 PMCID: PMC10960809 DOI: 10.1038/s41467-024-46748-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 03/08/2024] [Indexed: 03/25/2024] Open
Abstract
The diffusion model is used to calculate both the time-averaged flow of particles in stochastic media and the propagation of waves averaged over ensembles of disordered static configurations. For classical waves exciting static disordered samples, such as a layer of paint or a tissue sample, the flux transmitted through the sample may be dramatically enhanced or suppressed relative to predictions of diffusion theory when the sample is excited by a waveform corresponding to a transmission eigenchannel. Even so, it is widely assumed that the velocity of waves is irretrievably randomized in scattering media. Here we demonstrate in microwave measurements and numerical simulations that the statistics of velocity of different transmission eigenchannels are distinct and remains so on all length scales and are identical on the incident and output surfaces. The interplay between eigenchannel velocities and transmission eigenvalues determines the energy density within the medium, the diffusion coefficient, and the dynamics of propagation. The diffusion coefficient and all scattering parameters, including the scattering mean free path, oscillate with the width of the sample as the number and shape of the propagating channels in the medium change.
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Affiliation(s)
- Azriel Z Genack
- Department of Physics, Queens College of the City University of New York, Flushing, NY, 11367, USA.
- Physics Program, The Graduate Center of the City University of New York, New York, NY, 10016, USA.
| | - Yiming Huang
- Department of Physics, Queens College of the City University of New York, Flushing, NY, 11367, USA
- Physics Program, The Graduate Center of the City University of New York, New York, NY, 10016, USA
- Jinhua No.1 High School, Zhejiang, 321000, China
| | - Asher Maor
- Department of Physics, Queens College of the City University of New York, Flushing, NY, 11367, USA
- Physics Program, The Graduate Center of the City University of New York, New York, NY, 10016, USA
- Kent Optronics Inc., Hopewell Junction, New York, NY, 12533, USA
| | - Zhou Shi
- Department of Physics, Queens College of the City University of New York, Flushing, NY, 11367, USA
- Physics Program, The Graduate Center of the City University of New York, New York, NY, 10016, USA
- OFS Labs, 19 School House Road, Somerset, NJ, 08873, USA
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Falak P, Lee T, Zahertar S, Shi B, Moog B, Brambilla G, Holmes C, Beresna M. Compact high-resolution FBG strain interrogator based on laser-written 3D scattering structure in flat optical fiber. Sci Rep 2023; 13:8805. [PMID: 37258696 DOI: 10.1038/s41598-023-35708-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 05/22/2023] [Indexed: 06/02/2023] Open
Abstract
We demonstrate a fiber Bragg grating (FBG) strain interrogator based on a scattering medium to generate stable and deterministic speckle patterns, calibrated with applied strain, which are highly dependent on the FBG back-reflection spectral components. The strong wavelength-dependency of speckle patterns was previously used for high resolution wavemeters where scattering effectively folds the optical path, but instability makes practical realization of such devices difficult. Here, a new approach is demonstrated by utilizing femtosecond laser-written scatterers inside flat optical fiber, to enhance mechanical stability. By inscribing 15 planes of pseudo-randomized nanovoids (714 [Formula: see text] 500 voids per plane) as a 3D array in a 1 [Formula: see text] 0.7 [Formula: see text] 0.16 mm volume, the intrinsic stability and compactness of the device was improved. Operating as a wavemeter, it remained stable for at least 60 h with 45 pm resolution over the wavelength range of 1040-1056 nm. As a reflection mode FBG interrogator, after calibrating speckle patterns by applying tensile strain to the FBG, the device is capable of detecting microstrain changes in the range of 0-200 [Formula: see text] with a standard error of 4 [Formula: see text], limited by the translation stage step size. All these characteristics make it an interesting technology for filling the niche of low-cost, high-resolution wavemeters and interrogators which offer the best available trade-off between resolution, compactness, price and stability.
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Affiliation(s)
- Przemyslaw Falak
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Timothy Lee
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, UK
| | - Shahrzad Zahertar
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, UK
| | - Bo Shi
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, UK
| | - Bruno Moog
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, UK
| | - Gilberto Brambilla
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, UK
| | - Christopher Holmes
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, UK
| | - Martynas Beresna
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, UK
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Han S, Bender N, Cao H. Tailoring 3D Speckle Statistics. PHYSICAL REVIEW LETTERS 2023; 130:093802. [PMID: 36930913 DOI: 10.1103/physrevlett.130.093802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
We experimentally generate three-dimensional speckles with customized intensity statistics. By appropriately modulating the phase front of a laser beam, the far-field speckles can maintain a desired intensity probability density function upon axial propagation: while evolving into different spatial patterns. We also demonstrate how to design speckle patterns that obtain distinct tailored intensity statistics on multiple designated axial planes. The ability to design 3D speckle statistics opens many possibilities: three-dimensional imaging and sensing, optical trapping, and manipulation.
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Affiliation(s)
- SeungYun Han
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Nicholas Bender
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14850, USA
| | - Hui Cao
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
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Zhang C, Xin Y, Zhu X. Multiscale and local engineering of speckle morphology through disordered media. OPTICS LETTERS 2022; 47:6029-6032. [PMID: 37219164 DOI: 10.1364/ol.474976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 10/25/2022] [Indexed: 05/24/2023]
Abstract
In this Letter, we prompt a novel, to the best of our knowledge, method based on transmission matrix decomposition with wavelets to engineer the speckle morphology behind disordered media. By analyzing the speckles in multiscale spaces, we experimentally realized multiscale and localized control on the speckle size, position-dependent spatial frequency, and global morphology by operating on the decomposition coefficients using different masks. Speckles with contrasting features in different parts of the fields can be generated in one step. Our experimental results demonstrate a high degree of flexibility in manipulating light in a customizable manner. This technique has stimulating prospects in correlation control and imaging under scattering conditions.
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