Reflective Microscope Objectives
  • Wide spectral band
  • Long working distances
  • High numerical apertures
  • Zero chromatic aberration
  • Negligible coma, spherical, and astigmatic aberrations
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General Description Models

Construction

Newport's reflective microscope objectives are fabricated from a single material providing a uniform thermal coefficient of expansion. Each objective contains two highly polished electroless nickel spherical mirrors. The mirrors are coated with aluminum and magnesium fluoride. Average reflection per surface of each mirror is 85% in the UV-VIS, and 90% in the IR (with a dip to 76% at 820nm).

The primary mirror has a spherical concave surface with a center hole. The secondary mirror is a small convex spherical mirror that is machined into the spider assembly. The objectives are hand assembled in interferometric alignment fixtures allowing each pair of mirrors to be optimized as a set to achieve maximum resolution. Spot sizes of 2 µm for the 15X objective and 1µm for the 36X objective are typical.

How They Work

In a typical focusing application, collimated light passes through the aperture hole in the primary mirror to the secondary mirror. The secondary mirror reflects and diverges the beam to fill the primary mirror. The primary mirror focuses the beam to a small spot called the Object Plane or Focal Point.


A) Diagram of a typical focusing application of a reflective microscope objective
B) Illustration of the rear focal plane of a 160 mm back focal length objective


Applications
  • UV Metrology and Microscopy
  • Spatial Filtering
  • Photomicroscopy
  • Laser Energy Delivery Systems
  • FT-IR Spectroscopy

Specifications
 Model  Magnification  Numerical Aperture  BFL
(mm)
 Working Distance
(mm)
 Field of View
(mm)
 Focal Length
(mm)
 Obscuration
(%)
 Secondary Mirror Diameter
(mm)
 50105-01  15X  0.4  160  24.0  1.2  13.0  27  10.5
 50105-02  15X  0.4  Infinite  24.0  1.2  13.0  27  10.5
 50102-01  36X  0.52  160  10.4  0.5  5.4  17  5.6
 50102-02  36X  0.52  Infinite  10.4  0.5  5.4  17  5.6



Typical reflectance curves of metallic reflective coatings

Custom Reflective Microscope Objectives can be supplied with other magnification values and custom configurations.