ARC CoE for Engineered Quantum Systems and Optical Micromanipulation Group
School of Mathematics and Physics, The University of Queensland, Australia
The ability to sculpt light fields using spatial light modulators (SLM) or Digital Micromirror Devices (DMD) has given us tools of choice for the production of configurable and flexible confining potentials at the nano and micron-scale. We categorise the techniques used to create sculpted light to those based on time - averaged methods and those utilising spatial light modulators in either Fourier plane or direct imaging plane. A rapid angular modulation of Gaussian beam with a two-axis acousto-optic modulator, AOM, can be used as highly configurable time-averaged traps. This type of modulation has found applications in holographic tweezers and ringtraps for ultra-cold atoms. SLMs can be used as a way of producing extremely versatile structured light. SLMs in Fourier plane which control the phase and /or amplitude of an input Gaussian beam, with the pattern representing the spatial Fourier transform of the desired amplitude pattern. The optical system then focuses this sculpted light pattern to the plane containing the system of interests, performing a Fourier transform and recovering the desired pattern.
Yet another way for production of dynamical, fast and flexible structured light fields is using digital micromirror devices (DMD), which is based on direct imaging of amplitude patterns. DMD can configure the amplitude of an input beam either in the Fourier plane or in a direct imaging configuration.
Sculptured light produced using these methods promises high flexibility and an opportunity for trapping and driving systems ranging from studies of quantum thermodynamics using ultra cold atoms to trapping and manipulating nano and micron-size objects or even using these objects inside a biological cell and deep into the living tissue.