Page 236 - Optofluidics Fundamentals, Devices, and Applications

Bio-Inspir ed Fluidic Lenses for Imaging and Integrated Optics 211

Conic constant vs. curvature
20
18
3
16
16
14 2
Conic constant 12 8 1
10

6
0
4 0.1 0.15 0.2 0.25 0.3 0.35 0.4
2
0 0
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45
Curvature (1/mm)

FIGURE 9-5 (Continued)

9-2 Fluidic Lens for Imaging
It is helpful to briefly introduce how an optical system is designed.
Each surface of the lens in a system provides a certain amount of
converging (positive) or diverging (negative) power to the light beam.
Associated with the bending of the light by each lens surface is a
certain amount of aberration determined by the lens material and
profile. These aberrations, if not corrected, degrade the image quality.
According to the nature of aberrations, the effects on the final image
may be described as spherical aberration, coma, stigmatism, distor-
tion, axial color shift, lateral color shift, and the like. To achieve high-
quality images, optical designers use different lens surfaces to cancel
these aberrations. Readers interested to know how optical systems
are designed may find useful information in [Refs. 44 to 50].
Although the general methodology of optical design using fluidic
lenses is not different from that of a conventional system, one needs
to keep in mind that bio-inspired fluidic lens has an unprecedented
tuning range. If this property is effectively utilized, optical sys-
tems of unique functions can be obtained. In this section, we will
demonstrate that bio-inspired fluidic lens can produce the world’s
first miniature universal imager which integrates two systems, camera
and microscope, that are considered entirely incompatible in conven-
tional optics. The bio-inspired universal imager not only possesses
such unique functions but also has an extremely short (<1.2 cm) total