Multiphoton Physiology Objectives

Thorlabs now offers a selection of physiology objectives especially suited for Multiphoton Microscopy. These water-immersion objectives have a high numerical aperture (NA) as well as a long working distance (WD). Working Distance is defined as the distance between the tip of the scan lens housing and the front focal plane of the objective lens. Additionally, they are designed to have a wide transmission and color correction range.

In the case of Multiphoton Laser Scanning Microscopy, the objective focuses the collimated illumination beam that passes through the scanning system. The very low probability of a multiphoton absorption event occurring ensures signal is confined to the focal plane of the objective lens. Therefore, very little signal is generated outside the region above and below the focal plane. This effective elimination of out of focus signal means that the collected signal does not have to go back through the scanning system, thus allowing the detector to be placed as close to the objective as possible to maximize collection efficiency (as illustrated in the figure above).