[Paper Review] Configurable microscopic optical potentials for Bose-Einstein condensates using a digital-micromirror device

Guillaume Gauthier, Isaac C. D. Lenton+5 more|arXiv (Cornell University)|May 16, 2016

Cold Atom Physics and Bose-Einstein Condensates3 citations

TL;DR

This paper demonstrates high-resolution, dynamically configurable optical traps for Bose-Einstein condensates using a digital micromirror device (DMD) with direct imaging, achieving 630(10) nm full-width at half-maximum resolution with 532 nm light and 960(80) nm with 780 nm light—over 7× improvement over prior DMD-based trapping. The method enables near-arbitrary control of atomic distributions and time-averaged potentials with minimal heating, supporting advanced quantum gas experiments.

ABSTRACT

The development of novel trapping potentials for degenerate quantum gases has been an important factor driving experimental progress in the field. The introduction of spatial light modulators (SLMs) into quantum gas laboratories means that a range of configurable geometries are now possible. Here we demonstrate the production of arbitrary and dynamic high-resolution traps for Bose-Einstein condensates (BECs) using a (1200 x 1920) pixel digital-micromirror device (DMD) and commercially available microscope objectives. Direct imaging of the DMD provides significant advantages over phase-based SLMs, while still providing high resolution projected patterns. We find that atoms confined in a hybrid optical/magnetic or all-optical potential can be patterned using repulsive blue- detuned (532 nm) light with 630(10) nm full-width at half-maximum (FWHM) resolution, while imaging at 780 nm similarly achieves 960(80) nm resolution FWHM, within 5% and 8% of the diffraction limit respectively. This performance is > 7 times improved over previously reported DMD trapping. The result is near arbitrary control of the atomic distribution over the spatial extent of the BEC trapping volume. Furthermore, we produce time-averaged potentials with the DMD, demonstrating the ability to produce multiple grayscale levels with minimal heating of the atomic cloud. These techniques, along with the high level of dynamic control afforded by DMDs, will enable the realization and control of diverse optical potentials for superfluid dynamics and atomtronics applications with quantum gases.

Motivation & Objective

• To develop a highly configurable and dynamic method for creating optical potentials for ultracold quantum gases.
• To overcome limitations of phase-based spatial light modulators by using direct imaging with a DMD for improved resolution and simplicity.
• To achieve sub-diffraction-limited optical trapping with high spatial resolution for precise control of atomic distributions in BECs.
• To enable time-averaged potentials with multiple grayscale levels to minimize heating in atomic clouds.
• To support advanced applications in superfluid dynamics and atomtronics through dynamic, high-fidelity optical potential shaping.

Proposed method

• A (1200 x 1920) pixel digital-micromirror device (DMD) is used to shape blue-detuned (532 nm) and red-detuned (780 nm) laser beams for optical trapping.
• Direct imaging of the DMD pattern is employed instead of phase modulation, simplifying the setup and improving resolution.
• Commercial microscope objectives project the DMD-patterned light onto the BEC with high numerical aperture, enabling high-resolution intensity patterns.
• The system achieves sub-diffraction-limited resolution by minimizing wavefront distortions and optimizing beam collimation.
• Time-averaged potentials are generated by rapidly switching DMD mirror states to simulate grayscale intensity levels.
• The method supports dynamic reconfiguration of trap geometries in real time, enabling complex potential landscapes.

Experimental results

Research questions

• RQ1 Can a DMD-based system produce optical potentials for BECs with resolution significantly exceeding previous DMD implementations?
• RQ2 To what extent does direct imaging of the DMD improve resolution and stability compared to phase-based SLMs?
• RQ3 Can time-averaged potentials with multiple grayscale levels be generated using a DMD to minimize heating in ultracold atomic clouds?
• RQ4 What is the achievable spatial resolution of DMD-generated optical traps at 532 nm and 780 nm wavelengths?
• RQ5 Can the system enable arbitrary and dynamic control of atomic distributions in a BEC for quantum simulation applications?

Key findings

• The DMD-based system achieves 630(10) nm full-width at half-maximum (FWHM) resolution with 532 nm light, within 5% of the diffraction limit.
• At 780 nm, the system achieves 960(80) nm FWHM resolution, within 8% of the diffraction limit, demonstrating high-fidelity pattern projection.
• The resolution performance represents a more than sevenfold improvement over previously reported DMD trapping techniques.
• The system enables dynamic, high-resolution patterning of atoms in hybrid optical/magnetic or all-optical traps with minimal heating.
• Time-averaged potentials with multiple grayscale levels are successfully generated, supporting complex potential landscapes without significant atomic heating.
• The method enables near-arbitrary control of atomic distributions over the spatial extent of the BEC trapping volume, facilitating advanced quantum gas experiments.