Joel Carpenter

Author Correction: Time reversed optical waves by arbitrary vector spatiotemporal field generation

Publisher: Springer Science and Business Media LLC

Date: 18-01-2021

DOI: 10.1038/S41467-021-20944-8

Abstract: A Correction to this paper has been published: 0.1038/s41467-021-20944-8.

Spatial tomography of light resolved in time, spectrum, and polarisation

Publisher: Springer Science and Business Media LLC

Date: 25-07-2022

DOI: 10.1038/S41467-022-31814-2

Abstract: Measuring polarisation, spectrum, temporal dynamics, and spatial complex litude of optical beams is essential to studying phenomena in laser dynamics, telecommunications and nonlinear optics. Current characterisation techniques apply in limited contexts. Non-interferometric methods struggle to distinguish spatial phase, while phase-sensitive approaches necessitate either an auxiliary reference source or a self-reference, neither of which is universally available. Deciphering complex wavefronts of multiple co-propagating incoherent fields remains particularly challenging. We harness principles of spatial state tomography to circumvent these limitations and measure a complete description of an unknown beam as a set of spectrally, temporally, and polarisation resolved spatial state density matrices. Each density matrix slice resolves the spatial complex litude of multiple mutually incoherent fields, which over several slices reveals the spectral or temporal evolution of these fields even when fields spectrally or temporally overlap. We demonstrate these features by characterising the spatiotemporal and spatiospectral output of a vertical-cavity surface-emitting laser.

Time reversed optical waves by arbitrary vector spatiotemporal field generation

Publisher: Springer Science and Business Media LLC

Date: 16-11-2020

DOI: 10.1038/S41467-020-19601-3

Abstract: Lossless linear wave propagation is symmetric in time, a principle which can be used to create time reversed waves. Such waves are special “pre-scattered” spatiotemporal fields, which propagate through a complex medium as if observing a scattering process in reverse, entering the medium as a complicated spatiotemporal field and arriving after propagation as a desired target field, such as a spatiotemporal focus. Time reversed waves have previously been demonstrated for relatively low frequency phenomena such as acoustics, water waves and microwaves. Many attempts have been made to extend these techniques into optics. However, the much higher frequencies of optics make for very different requirements. A fully time reversed wave is a volumetric field with arbitrary litude, phase and polarisation at every point in space and time. The creation of such fields has not previously been possible in optics. We demonstrate time reversed optical waves with a device capable of independently controlling all of light’s classical degrees of freedom simultaneously. Such a class of ultrafast wavefront shaper is capable of generating a sequence of arbitrary 2D spatial olarisation wavefronts at a bandwidth limited rate of 4.4 THz. This ability to manipulate the full field of an optical beam could be used to control both linear and nonlinear optical phenomena.

Laguerre-Gaussian mode sorter

Publisher: Springer Science and Business Media LLC

Date: 26-04-2019

DOI: 10.1038/S41467-019-09840-4

Abstract: Exploiting a particular wave property for a particular application necessitates components capable of discriminating in the basis of that property. While spectral or polarisation decomposition can be straightforward, spatial decomposition is inherently more difficult and few options exist regardless of wave type. Fourier decomposition by a lens is a rare simple ex le of a spatial decomposition of great practical importance and practical simplicity a two-dimensional decomposition of a beam into its linear momentum components. Yet this is often not the most appropriate spatial basis. Previously, no device existed capable of a two-dimensional decomposition into orbital angular momentum components, or indeed any discrete basis, despite it being a fundamental property in many wave phenomena. We demonstrate an optical device capable of decomposing a beam into a Cartesian grid of identical Gaussian spots each containing a single Laguerre-Gaussian component, using just a spatial light modulator and mirror.

Reconfigurable structured light generation in a multicore fibre amplifier

Publisher: Springer Science and Business Media LLC

Date: 10-08-2020

DOI: 10.1038/S41467-020-17809-X

Abstract: Structured light, with spatially varying phase or polarization distributions, has given rise to many novel applications in fields ranging from optical communication to laser-based material processing. However the efficient and flexible generation of such beams from a compact laser source at practical output powers still remains a great challenge. Here we describe an approach capable of addressing this need based on the coherent combination of multiple tailored Gaussian beams emitted from a multicore fibre (MCF) lifier. We report a proof-of-concept structured light generation experiment, using a cladding-pumped 7-core MCF lifier as an integrated parallel lifier array and a spatial light modulator (SLM) to actively control the litude, polarization and phase of the signal light input to each fibre core. We report the successful generation of various structured light beams including high-order linearly polarized spatial fibre modes, cylindrical vector (CV) beams and helical phase front optical vortex (OV) beams.

Control of the temporal and polarization response of a multimode fiber

Publisher: Springer Science and Business Media LLC

Date: 08-11-2019

DOI: 10.1038/S41467-019-13059-8

Abstract: Control of the spatial and temporal properties of light propagating in disordered media have been demonstrated over the last decade using spatial light modulators. Most of the previous studies demonstrated spatial focusing to the speckle grain size, and manipulation of the temporal properties of the achieved focus. In this work, we demonstrate an approach to control the total temporal impulse response, not only at a single speckle grain but over all spatial degrees of freedom (spatial and polarization modes) at any arbitrary delay time through a multimode fiber. Global enhancement or suppression of the total light intensity exiting a multimode fibre is shown for arbitrary delays and polarization states. This work could benefit to applications that require pulse delivery in disordered media.

University Of Queensland

Location: Australia

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Discovery Projects - Grant ID: DP170101400

Start Date: 03-2017

End Date: 12-2020

Amount: $477,500.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP170100720

Start Date: 01-2019

End Date: 01-2023

Amount: $385,000.00

Funder: Australian Research Council

Discovery Early Career Researcher Award - Grant ID: DE180100009

Start Date: 06-2018

End Date: 12-2021

Amount: $365,058.00

Funder: Australian Research Council

ARC Future Fellowships - Grant ID: FT220100103

Start Date: 2023

End Date: 12-2026

Amount: $940,168.00

Funder: Australian Research Council