Equivalent Optical System Concept to Verify the Optical Working Distance in GRIN Rod Lens Imaging Probe

Abstract

This paper presents the concept of an equivalent optical system, specifically an equivalent test optical system for a gradient index (GRIN) rod lens imaging probe with a high optical numerical aperture. The purpose is to validate whether the optical working distance of a GRIN rod lens optical system aligns with the initially targeted value during the assembly process. We apply this concept to the assembly of our miniature photoacoustic imaging probe, which results in a significant improvement in the success rate of related work. We discuss the importance of this validation concept and the design precautions necessary for implementing a GRIN lens imaging probe, exemplified by our photoacoustic imaging probe.