Interference-free superposition of nonzero order light modes : Functionalized optical landscapes

In this paper, we utilize the incoherent superposition of nonzero order light modes. We show that this approach brings an additional degree of freedom to the generation of optical fields and notably the formation of superpositions that are otherwise unattainable through the use of refractive or diffractive optical elements and coherent or incoherent light sources. We employ this technique in two exemplary cases: first to create a field with tunable orbital angular momentum whose spatial intensity distribution remains unchanged and second to form an unusual type of "nondiffracting" light beam.Publisher PDFPeer reviewe

Wavefront corrected light sheet microscopy in turbid media

This project was supported by the UK Engineering and Physical Sciences Research Council.Light sheet microscopy is a powerful method for three-dimensional imaging of large biological specimens. However, its imaging ability is greatly diminished by sample scattering and aberrations. Optical clearing, Bessel light modes, and background rejection have been employed in attempts to circumvent these deleterious effects. We present an in situ wavefront correction that offers a major advance by creating an “optimal” light sheet within a turbid sample. Crucially, we show that no tissue clearing or specialized sample preparation is required, and clear improvements in image quality and depth resolution are demonstrated both in Gaussian and Bessel beam-based light sheet modalities.Publisher PDFPeer reviewe

Optical aberration compensation in a multiplexed optical trapping system

In this paper we discuss optical aberrations within a multiplexed optical trapping system. We analyze two of the most powerful methods for optical trap multiplexing: time-shared beam steering and holographic beam shaping in a tandem system with an acousto-optic deflector and spatial light modulator. We show how to isolate and correct for the aberrations introduced by these individual optical components using the spatial light modulator and demonstrate theenhancement this provides to optical trapping

Light-sheet microscopy using an Airy beam

Light-sheet microscopy facilitates rapid, high-contrast, volumetric imaging with minimal sample exposure. However, the rapid divergence of a traditional Gaussian light sheet restricts the field of view (FOV) that provides innate subcellular resolution. We show that the Airy beam innately yields high contrast and resolution up to a tenfold larger FOV. In contrast to the Bessel beam, which also provides an increased FOV, the Airy beam's characteristic asymmetric excitation pattern results in all fluorescence contributing positively to the contrast, enabling a step change for light-sheet microscopy

Towards Four-Dimensional Particle Tracking For Biological Applications

Observing biological processes in real-time and in single live cells is a vital step towards understanding cell behaviour and the way cells interact with the world around them. However, this requires real time three dimensional (4D) tracking of nanoparticles which is challenging and traditionally relies on sequential capture of 2D images to construct a 3D picture. We discuss a new approach to 4D nanoparticle tracking that utilises a specially designed diffraction grating which behaves as a lens with a different focal length in each diffraction order thereby producing pseudo 3D imaging over the imaged field. The current experimental system has the ability to track a single particle in a 50x50x6μm volume, with an accuracy of better than 50 nm in each dimension

Towards Four-Dimensional Particle Tracking For Biological Applications

Observing biological processes in real-time and in single live cells is a vital step towards understanding cell behaviour and the way cells interact with the world around them. However, this requires real time three dimensional (4D) tracking of nanoparticles which is challenging and traditionally relies on sequential capture of 2D images to construct a 3D picture. We discuss a new approach to 4D nanoparticle tracking that utilises a specially designed diffraction grating which behaves as a lens with a different focal length in each diffraction order thereby producing pseudo 3D imaging over the imaged field. The current experimental system has the ability to track a single particle in a 50x50x6μm volume, with an accuracy of better than 50 nm in each dimension