scholarly journals Investigation on the Formation of Laser Transverse Pattern Possessing Optical Lattices

2022 ◽  
Vol 9 ◽  
Author(s):  
Xin Wang ◽  
Zilong Zhang ◽  
Yuan Gao ◽  
Suyi Zhao ◽  
Yuchen Jie ◽  
...  
Keyword(s):  
Optical Lattices ◽  
Beat Frequency ◽  
Transverse Mode ◽  
Mode Locking ◽  
Vortex Lattices ◽  
Transverse Modes ◽  
Fixed Phase ◽  
Phase Singularities ◽  
Complex Symmetric ◽  
Transverse Pattern

Optical lattices (OLs) with diverse transverse patterns and optical vortex lattices (OVLs) with special phase singularities have played important roles in the fields of atomic cooling, particle manipulation, quantum entanglement, and optical communication. As a matter of consensus until now, the OL patterns are generated by coherently superimposing multiple transverse modes with a fixed phase difference through the transverse mode locking (TML) effect. There are phase singularities in the dark area of this kind of OL pattern, so it is also called OVL pattern. However, in our research, it is found that some high-order complex symmetric OL patterns can hardly be analyzed by TML model. Instead, the analysis method of incoherent superposition of mode intensity could be applied. The OL pattern obtained by this method can be regarded as in non-TML state. Therefore, in this article, we mainly study the distinct characteristics and properties of OL patterns in TML and non-TML states. Through intensity comparison, interferometry, and beat frequency spectrum, we can effectively distinguish OL pattern in TML and non-TML states, which is of significance to explore the formation of laser transverse pattern possessing OL.

scholarly journals Spatiotemporal mode-locking in multimode fiber lasers

Science ◽  
2017 ◽  
Vol 358 (6359) ◽  
pp. 94-97 ◽  
Author(s):  
Logan G. Wright ◽  
Demetrios N. Christodoulides ◽  
Frank W. Wise
Keyword(s):  
Fiber Lasers ◽  
Ultrashort Pulses ◽  
Transverse Mode ◽  
Mode Locking ◽  
Multimode Fiber ◽  
Nonlinear Wave Propagation ◽  
Longitudinal Modes ◽  
Light Pulses ◽  
Transverse Modes ◽  
Ultrafast Science

A laser is based on the electromagnetic modes of its resonator, which provides the feedback required for oscillation. Enormous progress has been made toward controlling the interactions of longitudinal modes in lasers with a single transverse mode. For example, the field of ultrafast science has been built on lasers that lock many longitudinal modes together to form ultrashort light pulses. However, coherent superposition of longitudinal and transverse modes in a laser has received little attention. We show that modal and chromatic dispersions in fiber lasers can be counteracted by strong spatial and spectral filtering. This allows locking of multiple transverse and longitudinal modes to create ultrashort pulses with a variety of spatiotemporal profiles. Multimode fiber lasers thus open new directions in studies of nonlinear wave propagation and capabilities for applications.

scholarly journals Supernova constraints on an axion-photon-dark photon interaction

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Anson Hook ◽  
Gustavo Marques-Tavares ◽  
Clayton Ristow
Keyword(s):  
Longitudinal Mode ◽  
Transverse Mode ◽  
The Other ◽  
Unusual Feature ◽  
Dark Sector ◽  
Longitudinal Modes ◽  
Dark Photon ◽  
Transverse Modes ◽  
Weakly Coupled ◽  
Photon Coupling

Abstract We present the supernova constraints on an axion-photon-dark photon coupling, which can be the leading coupling to dark sector models and can also lead to dramatic changes to axion cosmology. We show that the supernova bound on this coupling has two unusual features. One occurs because the scattering that leads to the trapping regime converts axions and dark photons into each other. Thus, if one of the two new particles is sufficiently massive, both production and scattering become suppressed and the bounds from bulk emission and trapped (area) emission both weaken exponentially and do not intersection The other unusual feature occurs because for light dark photons, longitudinal modes couple more weakly than transverse modes do. Since the longitudinal mode is more weakly coupled, it can still cause excessive cooling even if the transverse mode is trapped. Thus, the supernova constraints for massive dark photons look like two independent supernova bounds super-imposed on top of each other.

Optimum Multi-Nozzle Configuration for Minimizing the Rayleigh Integral During High-Frequency Transverse Instabilities

2021 ◽  
Author(s):  
Vishal Acharya ◽  
Tim Lieuwen
Keyword(s):  
High Frequency ◽  
Transverse Mode ◽  
Acoustic Mode ◽  
Combustion Stability ◽  
Circular Distribution ◽  
Transverse Modes ◽  
Fixed Set ◽  
Circular Configuration ◽  
Swirling Strength ◽  
The Stability

Abstract This paper develops a formalism for optimizing nozzle location/configuration with respect to combustion stability of high-frequency transverse modes in a can combustor. The stability of these acoustically non-compact flames was assessed using the Rayleigh Integral (RI). Several key control parameters influence RI - flame angle, swirling strength, nozzle location, as well as nozzle location with respect to the acoustic mode shape. In this study, we consider a N-around-1 configuration such as typically used in a multi-nozzle can system and study the overall stability of this system for different natural transverse modes. Typically, such nozzles are distributed in a uniformly circular manner for which we study the overall RI and for cases where RI>0, we optimize the nozzle distribution that can reduce and minimize RI. For a fixed geometry such a circular configuration, the analysis shows how the flame's parameters must vary across the different nozzles, to result in a relatively stable system. Additionally, for a fixed set of flame parameters, the analysis also indicates the non-circular distribution of the N nozzles that minimizes RI. Overall, the analysis aims to provide insights on designing nozzle locations around the center nozzle for minimal amplification of a given transverse mode.

scholarly journals Modal reconstruction of transverse mode-locked laser beams

2020 ◽  
Vol 126 (10) ◽  
Author(s):  
Florian Schepers ◽  
Tim Hellwig ◽  
Carsten Fallnich
Keyword(s):  
Power Distribution ◽  
Oscillation Amplitude ◽  
Transverse Mode ◽  
Mode Locking ◽  
Orthogonal Direction ◽  
Modal Power ◽  
Gradient Descent Algorithm ◽  
Stochastic Parallel Gradient Descent ◽  
Spatio Temporal ◽  
Mode Order

Abstract Transverse mode-locking in an end-pumped solid state laser by amplitude modulation with an acousto-optic modulator was investigated. Using the stochastic parallel gradient descent algorithm the modal power coefficients and the modal phases of the transverse mode-locked (TML) laser beam were reconstructed from the measured spatial and spatio-temporal intensity distributions, respectively. The distribution of the reconstructed modal power coefficients revealed that the average mode order of the transverse mode-locking process could be increased by a factor of about 8 compared to previous works, corresponding to an increase in the normalized oscillation amplitude by a factor of about 3. Furthermore, we found that besides a non-Poissonian modal power distribution, strong aberrations of the modal phases occurred in the experiment, resulting in a deformation of the oscillating spot. Additionally, we demonstrated the generation of up to four spots oscillating simultaneously on parallel traces by operating the TML laser on a higher mode order in the orthogonal direction to the transverse mode-locking process. TML lasers are of interest, e.g., for beam scanning purposes, as they have the potential to enable spot resolving rates in the multi-GHz regime.

scholarly journals Mode Locking in ac-Driven Vortex Lattices with Random Pinning

2001 ◽  
Vol 86 (18) ◽  
pp. 4112-4115 ◽  
Author(s):  
Alejandro B. Kolton ◽  
Daniel Domínguez ◽  
Niels Grønbech-Jensen
Keyword(s):  
Mode Locking ◽  
Vortex Lattices
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