Off-axis parabolic mirror relay microscope for experiments with ultra-cold matter

Area of Science:

• Atomic, Molecular, and Optical Physics
• Cryogenics and Vacuum Technology
• Optical Engineering

Background:

• Imaging Coulomb crystals in cryogenic ion traps is challenging due to space constraints near the ions.
• Standard microscope objectives require close proximity and direct line-of-sight, which are often unfeasible in such setups.
• Existing methods limit the resolution and accessibility of ion trap experiments.

Purpose of the Study:

• To introduce a new optical system for imaging Coulomb crystals in space-limited cryogenic ion traps.
• To demonstrate a high-resolution imaging solution that bypasses the need for conventional microscope objectives.
• To enable detailed observation of ion lattices under extreme cryogenic conditions.

Main Methods:

• Development of an off-axis parabolic (OAP) mirror relay microscope.
• Utilizing two 90-degree OAP mirrors to relay images from the ion trap.
• Integrating standard microscope optics for image delivery to a camera.
• Operating the system within an ultra-high-vacuum vessel at temperatures below 10 K.

Main Results:

• The OAP mirror relay system successfully imaged Coulomb crystals.
• Achieved resolution of features smaller than the inter-ion separation in Coulomb crystals.
• Demonstrated high-resolution imaging without direct line-of-sight or close-proximity viewports.
• Confirmed the feasibility of imaging in ultra-high vacuum below 10 K.

Conclusions:

• Off-axis parabolic mirrors offer a novel solution for imaging in restricted environments like cryogenic ion traps.
• This optical system overcomes limitations of traditional microscopy for observing Coulomb crystals.
• The OAP mirror relay enables micrometer-scale resolution imaging over extended distances in challenging conditions.