arXiv subjects

Peter J. Reece

Publications and source records attributed to Peter J. Reece.

4 recordsLinked to original sources

arXiv2026

Rotating fluorescent nanodiamond assemblies with focused Laguerre-Gaussian beams

Optical tweezers which utilize structured light fields enable the rotation of trapped nanoparticles through the transfer of orbital angular momentum (OAM) from holographically generated Laguerre-Gaussian (LG) modes. In this research we use OAM transfer to demonstrate controlled rotation of bright fluorescent nanodiamond clusters assembled in a focused higher-order LG beam. We find that the assemblies can be effectively rotated in a two-dimensional optical trap with orbital frequencies of up to 5 Hz. We use video tracking to explore the Brownian dynamics of such a trapping arrangement and look at the impact of orientation stability on measurements of optically detected magnetic resonance (ODMR) with an applied weak external magnetic field. By collecting ODMR spectra at multiple points along the orbit, we show that the constrained two-dimensional motion can provide additional insights for vector magnetic field reconstruction.

physics.optics↗

arXiv2022

Roadmap for Optical Tweezers

Optical tweezers are tools made of light that enable contactless pushing, trapping, and manipulation of objects ranging from atoms to space light sails. Since the pioneering work by Arthur Ashkin in the 1970s, optical tweezers have evolved into sophisticated instruments and have been employed in a broad range of applications in life sciences, physics, and engineering. These include accurate force and torque measurement at the femtonewton level, microrheology of complex fluids, single micro- and nanoparticle spectroscopy, single-cell analysis, and statistical-physics experiments. This roadmap provides insights into current investigations involving optical forces and optical tweezers from their theoretical foundations to designs and setups. It also offers perspectives for applications to a wide range of research fields, from biophysics to space exploration.

physics.optics↗

arXiv2015

Anomalous dynamic behaviour of optically trapped high aspect ratio nanowires

We investigate the dynamics of high aspect ratio nanowires trapped axially in a single gradient force optical tweezers. A power spectrum analysis of the Brownian dynamics reveals a broad spectral resonance of the order of a kHz with peak properties that are strongly dependent on the input trapping power. Modelling of the dynamical equations of motion of the trapped nanowire that incorporate non-conservative effects through asymmetric coupling between translational and rotational degrees of freedom provides excellent agreement with the experimental observations. An associated observation of persistent cyclical motion around the equilibrium trapping position using winding analysis provides further evidence for the influence of non-conservative forces.

physics.optics↗

arXiv2012

Theoretical and experimental evaluation of multilayer porous silicon structures for enhanced erbium up-conversion luminescence

The enhancement of Er$^{3+}$-based up-conversion for photovoltaics in multilayer porous silicon photonic structures is considered theoretically and experimentally. Transfer matrix simulations are used to assess the increased photonic density of states that results from the slowing of energy propagation at the short-wavelength edge of one-dimensional photonic band gaps. An indirect calculation of Er$^{3+}$ absorption enhancement within slow-light modes is then used to illustrate an increase in absorption over the bulk value: the effective absorption coefficient is shown to increase by more than 22% over a broad spectral region and by more than 400% over a narrow region. Erbium-doped porous silicon photonic crystals are fabricated with the photonic band edge coincident with the $^{4}I_{15/2} \rightarrow^{4}I_{13/2}$ Er$^{3+}$ transition. Challenges in fabrication and the results of compositional analysis are discussed. An angular-dependent photoluminescence measurement demonstrates emission intensity that varies non-monotonically with the position of the photonic band edge. A maximum of 26.6$\times$ enhancement of Er$^{3+}$ emission intensity is observed for the 550-nm transition, with lower enhancement factors seen for longer wavelengths.

physics.optics↗