Single-step fabrication of surface waveguides in fused silica with few-cycle laser pulses

Furch, Federico J.; Engel, W.; Witting, Tobias; Vrakking, Marc J. J.; Mermillod–Blondin, Alexandre

doi:10.1364/ol.44.004267

Cited by 16 publications

(5 citation statements)

References 37 publications

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“…12,13 A recent trend in ultrashort laser processing relies on the use of few-cycle pulses, predicted to achieve ultimate precision, thus preparing a new generation of micro-processing tools. 14,15 They enable an extended processing control by tuning the interplay between multiphoton excitation and strong field ionization, 16 where the cycling of the laser pulse becomes critical.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast bandgap narrowing and cohesion loss of photoexcited fused silica

Tsaturyan

Kachan

Stoian

et al. 2022

The Journal of Chemical Physics

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Coupling and spatial localization of energy on the timescale of the excitation pulse in ultrashort laser irradiated dielectric materials are key elements for enabling processing precision beyond the optical limit. We apply a first-principles model to determine dynamic distortions of energy bands following the rapid increase in the free-carrier population in an amorphous dielectric excited by an ultrashort laser pulse. Fused silica glass is reproduced using a system of (SiO4)4- tetrahedra, where DFT extended to FT-DFT reproduces ground and photoexcited states. Triggered by electronic charge redistribution, a bandgap narrowing of more than 2 eV is shown to occur in fused silica under geometry relaxation. Calculations reveal that the bandgap decrease results from the rearrangement of atoms altering the bonding strength. Despite an atomic movement impacting strongly the structural stability, the observed change of geometry remains limited to 7% of the interatomic distance and occurs on the femtosecond timescale. This structural relaxation is thus expected to take place quasi-instantly following the photon energy flux. Moreover, under intense laser excitation, fused silica loses its stability when an electron temperature of around 2.8 eV is reached. Further increase of the excitation energy leads to the collapse of both structure and bandgap.

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Section: Introductionmentioning

confidence: 99%

Ultrafast bandgap narrowing and cohesion loss of photoexcited fused silica

Tsaturyan

Kachan

Stoian

et al. 2022

The Journal of Chemical Physics

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show abstract

“…The excitation with the corresponding coherent EM promotes these EPs to an arbitrary order in the emerging synthetic coupled structure in the

N

‐photon Fock‐space, and this without the need of further fine‐tuning of the loss‐rates in the underlying physical system. [ 44 ] Utilizing PNR detectors, it is then possible to exploit the effect of loss‐induced transparency in the quantum optical regime. We have outlined this concept for the semi‐lossy waveguide beamsplitter, which is excited by its coherent exceptional mode.…”

Section: Discussionmentioning

confidence: 99%

Branching High‐Order Exceptional Points in Non‐Hermitian Optical Systems

Tschernig

Busch

Christodoulides

et al. 2022

Laser & Photonics Reviews

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Exceptional points are complex‐valued spectral singularities that lead to a host of intriguing features such as loss‐induced transparency—a counterintuitive process in which an increase in the system's overall loss can lead to enhanced transmission. In general, the associated enhancements scale with the order of the exceptional points. Consequently, it is of great interest to devise new strategies to implement realistic devices capable of exhibiting high‐order exceptional points. Here, it is shown that high‐order N$N$‐photon exceptional points can be generated by exciting non‐Hermitian waveguide arrangements with coherent light states. Using photon‐number resolving detectors it then becomes possible to observe N$N$‐photon enhanced loss‐induced transparency in the quantum realm. Further, it is analytically shown that the number‐resolved dynamics occurring in the same nonconservative waveguide arrays will exhibit eigenspectral ramifications having several exceptional points associated to different sets of eigenmodes and dissipation rates.

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“…In this work we have shown that arrays of coupled waveguides exhibiting alternating patterns of lossy and lossless sites, gives rise to several EPs of second order at the single photon or, equivalently, the classical level. The excitation with the corresponding coherent EM promotes these EPs to an arbitrary order in the emerging synthetic coupled structure in the N -photon Fock-space, and this without the need of further fine-tuning of the loss-rates in the underlying physical system [41]. Utilizing PNR detectors, it is then possible to exploit the ef-fect of loss-induced transparency in the quantum optical regime.…”

Section: Discussionmentioning

confidence: 99%

Branching high-order exceptional points in non-hermitian optical systems

Tschernig¹,

Busch²,

Christodoulides³

et al. 2021

Preprint

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Exceptional points are complex-valued spectral singularities that lead to a host of intriguing features such as loss-induced transparency -a counterintuitive process in which an increase in the system's overall loss can lead to enhanced transmission. In general, the associated enhancements scale with the order of the exceptional points. Consequently, it is of great interest to devise new strategies to implement realistic devices capable of exhibiting high-order exceptional points. Here, we show that high-order N -photon exceptional points can be generated by exciting non-hermitian waveguide arrangements with coherent light states. Using photon-number resolving detectors it then becomes possible to observe N -photon enhanced loss-induced transparency in the quantum realm. Further, we analytically show that the number-resolved dynamics occurring in the same nonconservative waveguide arrays will exhibit eigenspectral ramifications having several exceptional points associated to different sets of eigenmodes and dissipation rates.

show abstract

Single-step fabrication of surface waveguides in fused silica with few-cycle laser pulses

Cited by 16 publications

References 37 publications

Ultrafast bandgap narrowing and cohesion loss of photoexcited fused silica

Ultrafast bandgap narrowing and cohesion loss of photoexcited fused silica

Branching High‐Order Exceptional Points in Non‐Hermitian Optical Systems

Branching high-order exceptional points in non-hermitian optical systems

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