arXiv subjects

S. G. Murdoch

Publications and source records attributed to S. G. Murdoch.

5 recordsLinked to original sources

arXiv2020

Phase and Intensity Control of Dissipative Kerr Cavity Solitons

Dissipative Kerr cavity solitons are pulses of light that can persist in coherently driven nonlinear optical resonators. They have attracted significant attention over the past decade due to their rich nonlinear dynamics and key role in the generation of coherent microresonator optical frequency combs. Whilst the vast majority of implementations have relied on \emph{homogeneous} continuous wave driving, the soliton's "plasticity" combined with \emph{inhomogeneous} driving offers attractive advantages for a host of applications. Here we review recent studies into the dynamics and applications of Kerr cavity solitons in the presence of inhomogeneous driving fields. In particular, we summarise the salient theoretical developments that allow for the analysis of CS motion in the presence of pump phase or amplitude inhomogeneities, and survey recent experiments that use pulsed driving to realise energy efficient and flexible microresonator optical frequency combs.

physics.optics↗

arXiv2016

Efficiency of dispersive wave generation from a dual-frequency beat signal

The emission of dispersive waves (DWs) by temporal solitons can be described as a cascaded four-wave mixing process triggered by a pair of monochromatic continuous waves (CWs). We report experimental and numerical results demonstrating that the efficiency of this process is strongly and non-trivially affected by the frequency detuning of the CW pump lasers. We explain our results by showing that individual cycles of the input dual-frequency beat signal can evolve as higher-order solitons whose temporal compression and soliton fission govern the DW efficiency. Analytical predictions based on the detuning dependence of the soliton order are shown to be in excellent agreement with experimental and numerical observations.

physics.optics↗

arXiv2006

Photon pair generation using four-wave mixing in a microstructured fibre: theory versus experiment

We develop a theoretical analysis of four-wave mixing used to generate photon pairs useful for quantum information processing. The analysis applies to a single mode microstructured fibre pumped by an ultra-short coherent pulse in the normal dispersion region. Given the values of the optical propagation constant inside the fibre, we can estimate the created number of photon pairs per pulse, their central wavelength and their respective bandwidth. We use the experimental results from a picosecond source of correlated photon pairs using a micro-structured fibre to validate the model. The fibre is pumped in the normal dispersion regime at 708nm and phase matching is satisfied for widely spaced parametric wavelengths of 586nm and 894nm. We measure the number of photons per pulse using a loss-independent coincidence scheme and compare the results with the theoretical expectation. We show a good agreement between the theoretical expectations and the experimental results for various fibre lengths and pump powers.

quant-ph↗

arXiv2001

Understanding the production of dual BEC with sympathetic cooling

We show, both experimentally and theoretically, that sympathetic cooling of $^{87}$Rb atoms in the $|F=2,m_F=2>$ state by evaporatively cooled atoms in the $|F=1,m_F=-1>$ state can be precisely controlled to produce dual or single condensate in either state. We also study the thermalization rate between two species. Our model renders a quantitative account of the observed role of the overlap between the two clouds and points out that sympathetic cooling becomes inefficient when the masses are very different. Our calculation also yields an analytical expression of the thermalization rate for a single species.

quant-ph↗

arXiv2000

RF-induced evaporative cooling and BEC in a high magnetic field

We present the design of our iron-core electromagnet for BEC, and how to solve the specific experimental problems raised by this technique. After presenting the experimental set-up, we address the interruption of runaway evaporative cooling when the Zeeman effect is not linear. We present the ways to circumvent this problem, use of multiple RF frequencies, sympathetic cooling and show some applications of these high magnetic fields (cavity coupling, high confinement).

physics.atom-ph↗