====== Expansion Objectives ======


===== History =====

Building on a collaboration begun with [[multi-immersion_objectives|multi-immersion objectives]], Applied Scientific Instrumentation (ASI) worked with Special Optics to develop dipping objective lenses for expansion samples.  The key feature includes a very long WD while keep good NA and large FOV.  We also minimized the profile of the mechanical tip given the NA/FOV.  The first objective will be available around September 2026, and other designs are expected to follow.

ASI is the sole distributor of these objectives but will sell them freely to anyone interested, including home builders and companies.



===== 57-15-8 Specifications =====

^  Specification            ^  Value                ^  Comments                                                     ^
|  Numerical Aperture      |  1.0       | water dipping, **not** multi-immersion                                   |
|  Effective Focal Length  |  7.49 mm     | 26.7x with 200 mm TL, 24x with 180 mm TL                    |
|  Working Distance        |  5.45 mm  |        |
|  Field of View           |  1.1 mm Ø            | diffraction-limited, slightly larger for some wavelengths  |
|  Corrections    |  plan apo | optimized for 500 – 750 nm   |
|  Transmission    |  ~85%     | Internal coatings 400 – 1300 nm   |          |
|  Parfocal length             |  83 mm |   |
|  Threads             |  M32x0.75 |   |
|  Mechanical Angle        |  53.1° / 48°          | measured from front of FOV to limiting point / slope of body |