Chaos-Preserving Reduction of the Spin-Flip Model for VCSELs: Failure of the Adiabatic Elimination of the Spin-Population Difference

Virte, Martin; Ferranti, Francesco

doi:10.1109/jstqe.2019.2921377

Cited by 3 publications

(1 citation statement)

References 40 publications

(81 reference statements)

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“…This can yield rate equations in two [34][35][36][37] and three [38][39][40] variables. However, it has recently been pointed out that these do not account for some dynamic effects of the system, including polarisation chaos [41]. Furthermore, whilst the improved three-variable reduction obtained via the method of multiple scales has been very successful in accounting for experimental results on polarisation switching in conventional VCSELs (see, e.g., [42,43]), its extension to reveal the key importance of the spin carrier population difference in spin-VCSELs has not been reported.…”

Section: Introductionmentioning

confidence: 99%

Three-Variable Reduction of the Spin-Flip Model for Spin-VCSELs

Adams

Huang

et al. 2022

IEEE J. Quantum Electron.

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Recent increased interest in spin-polarised vertical-cavity surface-emitting lasers (spin-VCSELs) as potential high-speed sources has spurred research into the analysis of their dynamics. This has often been explored by combining the spin-flip model (SFM) with numerical methods. However, numerical simulation does not readily expose key dependencies and to date there is a lack of accessible closed-form analytical results for the steady-state solutions and dynamic stability boundaries. Thus in the present contribution we address this and show that, for zero dichroism, the five rate equations of the SFM can be reduced to a set of three. These can be solved in the steady-state in terms of the intensity and polarisation of the pump (optical or electrical), and the ellipticity of the output. Additionally, a small-signal analysis leads to analytic results for the boundaries between stable and unstable operation in the plane of pump ellipticity versus pump intensity. Comparison of the results from these expressions with those from numerical bifurcation and continuation methods shows very good agreement. The accuracy of the reduced set of equations is confirmed by comparing the results with those from the full set of SFM equations. In the limiting case of very high birefringence, as would be required for a potential THz source, a simple algebraic relation is derived for the spin relaxation rate in terms of other parameters. Hence we find that the range of spin relaxation rates to achieve THz oscillations is very limited. The relative simplicity of the present approach thus offers a rapid, intuitive and convenient route to study the dynamics of spin-VCSELs.

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Section: Introductionmentioning

confidence: 99%

Three-Variable Reduction of the Spin-Flip Model for Spin-VCSELs

Adams

Huang

et al. 2022

IEEE J. Quantum Electron.

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Label-free imaging of collagen fibers in tissue slices using phase imaging with computational specificity

Sakakura

Popescu

Kajdacsy-Balla

et al. 2021

Preprint

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Evaluating the tissue collagen content in addition to the epithelial morphology has been proven to offer complementary information in histopathology, especially in disease stratification and patient survivability prediction. One imaging modality widely used for this purpose is second harmonic generation microscopy (SHGM), which reports on the nonlinear susceptibility associated with the collagen fibers. Another method is polarization light microscopy (PLM) combined with picrosirius-red (PSR) tissue staining. However, SHGM requires expensive equipment and provides limited throughput, while PLM and PSR staining are not part of the routine pathology workflow. Here, we advance phase imaging with computational specificity (PICS) to computationally infer the collagen distribution of unlabeled tissue, with high specificity. PICS utilizes deep learning to translate quantitative phase images (QPI) into corresponding PSR images with high accuracy and speed. Our results indicate that the distributions of collagen fiber orientation, length, and straightness reported by PICS closely match the ones from ground truth.

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Leader-laggard synchronization of polarization chaos in mutually coupled free-running VCSELs

Zhang¹,

Li²,

Jia³

et al. 2023

Opt. Express

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We systematically study the leader-laggard synchronization of polarization chaos in mutually coupled free-running vertical cavity surface emitting semiconductor lasers in two cases of parallel and orthogonal injection. Specifically, we quantitatively investigate the effect of critical external parameter mismatch such as the coupling intensity and frequency detuning on the leader-laggard relationship utilizing the cross-correlation function. When the difference between two main cross-correlation peak values exceeds 0.1, the leader-laggard relationship can be viewed to be stable. Our results demonstrate that compared with the coupling strength, the frequency detuning is the dominant factor in determining the stability of the leader-laggard relationship. The exchange of the leader-laggard role occurs within a frequency detuning region from -5 GHz to 5 GHz for both parallel and orthogonal injection. Once the leader-laggard relationship is stable, the difference between the two cross-correlation values can reach 0.242 for negative frequency detuning, but the corresponding value is only 0.146 under positive frequency detuning.

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Chaos-Preserving Reduction of the Spin-Flip Model for VCSELs: Failure of the Adiabatic Elimination of the Spin-Population Difference

Cited by 3 publications

References 40 publications

Three-Variable Reduction of the Spin-Flip Model for Spin-VCSELs

Three-Variable Reduction of the Spin-Flip Model for Spin-VCSELs

Label-free imaging of collagen fibers in tissue slices using phase imaging with computational specificity

Leader-laggard synchronization of polarization chaos in mutually coupled free-running VCSELs

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