Coherence switching of a degenerate VECSEL for multimodality imaging

Knitter, Sebastian; Liu, Changgeng; Redding, Brandon; Choma, Michael A.; Cao, Hui

doi:10.1364/cleo_at.2016.am3o.4

“…Fast speckle suppression is essential for time-resolved imaging of moving targets or transient phenomena [10][11][12]. It can be achieved by using multimode lasers with low and tunable spatial coherence [13][14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Fast laser speckle suppression with an intracavity diffuser

Mahler

¹

,

Eliezer

²

,

Yılmaz

³

et al. 2020

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Fast speckle suppression is crucial for time-resolved full-field imaging with laser illumination. Here, we introduce a method to accelerate the spatial decoherence of laser emission, achieving speckle suppression in the nanosecond integration time scale. The method relies on the insertion of an intracavity phase diffuser into a degenerate cavity laser to break the frequency degeneracy of transverse modes and broaden the lasing spectrum. The ultrafast decoherence of laser emission results in the reduction of speckle contrast to 3% in less than 1 ns.

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“…Fast speckle suppression is essential for time-resolved imaging of moving targets or transient phenomena [10][11][12]. It can be achieved by using multimode lasers with low and tunable spatial coherence on demand [13][14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Accelerating speckle suppression by a degenerate cavity laser with an intracavity phase diffuser

Mahler,

Eliezer,

Yılmaz

et al. 2020

Preprint

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0

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Fast speckle suppression is crucial for time-resolved full-field imaging with laser illumination. Here, we introduce a method to accelerate the spatial decoherence of laser emission, achieving speckle suppression in the nanosecond integration time scale. The method relies on the insertion of an intracavity phase diffuser into a degenerate cavity laser to break the frequency degeneracy of transverse modes and broaden the lasing spectrum. The ultrafast decoherence of laser emission results in the reduction of speckle contrast to 3% in less than 1 nanosecond.

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“…They can display a large optical output power 2 and excellent beam quality, which are, for instance, crucial for medical or biological imaging applications. 3 The most striking feature exhibited by these lasers is their high spectral purity and low intensity noise allowed by their class-A dynamical behavior. This is made possible by their cavity photon lifetime, which is typically one order of magnitude longer than the lifetime of semiconductor carriers, 4 preventing relaxation oscillations from appearing.…”

Section: Introductionmentioning

confidence: 99%

Thermal phase fluctuations in optically pumped dual-frequency vertical external-cavity surface-emitting lasers for cesium clocks based on coherent population trapping

Gredat

¹

,

Liu

²

,

Bretenaker

³

2019

Journal of Applied Physics

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A fully analytical model is established for the thermal fluctuations of the beatnote phase of an optically pumped dual-frequency vertical-external-cavity surface-emitting laser (VECSEL). This model starts with the resolution of the heat equation inside the semiconductor chip structure and follows with the evaluation of the induced thermo-optic phase shift. Both the fluctuations of the heat induced by the optical pumping and the thermodynamic fluctuations at room temperature are considered. On the one hand, the thermal response of the structure is investigated and a significant thermal lens effect caused by the pump is deduced. On the other hand, the power spectral density of the frequency noise is calculated in the presence of diffusion spatial anisotropy. The present model is in very good agreement with the phase noise measured for a dual-frequency VECSEL at 852 nm for application to metrology and the validity of the usual low-pass filter model is discussed.

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Coherence switching of a degenerate VECSEL for multimodality imaging

Cited by 13 publications

References 1 publication

Fast laser speckle suppression with an intracavity diffuser

Fast laser speckle suppression with an intracavity diffuser

Accelerating speckle suppression by a degenerate cavity laser with an intracavity phase diffuser

Thermal phase fluctuations in optically pumped dual-frequency vertical external-cavity surface-emitting lasers for cesium clocks based on coherent population trapping

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