PowerPoint Presentation - Intro to Optics

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Optics
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Thomas Young (1773 - 1829)
Christiaan Huygens (1629 - 1695)
Wave Optics Diffraction Interference
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Ripple Tank
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Diffraction is a characteristic of wave dynamics
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Diffraction
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Airy Disk Diffraction Pattern
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Airy Disk
George Biddell Airy
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Interference
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Constructive interference
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Destructive interference
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Thomas Young (1773 - 1829)
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Single Photon Sources
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e-
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Interference
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The lens is a light gathering instrument that
collects a cone of light emanating from the object
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Basic optics simple thin lens
O
I
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Basic optics simple thin lens
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f
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Basic optics simple thin lens
f
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f
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1/I 1/O 1/f mag -I/O
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Image Formation
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Image Magnification
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Spherical Aberration
non-paraxial rays do not meet at the paraxial
focus
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Spherical Aberration can be reduced by
introducing additional carefully designed lenses
into the optical path. Each lens element
scatters light and costs photons -- resulting in
loss of image contrast
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Spherical Aberration of a Point Source
Negative
Zero
Positive
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Chromatic Aberrations is due to wavelength
dependence of refractive index of transparent
media
Can be reduced by coating lens elements to
selectively correct refraction of various
wavelengths
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lenses corrected for achromatic aberration
uncorrected
achromatic
semi-apochromatic
apochromatic
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Objective lenses
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Single Lens Imaging System
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Anatomy of a Compound Microscope
trinocular tube
eye piece
objective turret
stand
stage
substage condenser
base
lamp housing
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Nomenclature
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Correction collars
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Robert Hooke (1635 - 1703)
Built one of the first useful compound
microscopes Observed structure of cork Coined the
term Cell. Published Micrographia (1665)
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1665 Hooke publishes Micrographia 1678
van Leeuwenhoek observes protozoa (little
animals) 1838-9 Schleiden Schwann proposed
Cell Theory 1860 Pasteur confirms Cell
Theory 1931 Ruska invents electron
microscope 1932 Zerniki develops phase
contrast microscopy 1955 Minsky invents the
laser scanning microscope (LSM) 1989 Webb,
Denk Strickler invent multiphoton LSM
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Light Microscopy
Upright Microscope
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Upright Microscope
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Upright Microscope
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Objective Lens
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Upright Microscope
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Upright Microscope
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• Specimen
  
• Must be transparent to visible light
• Usually either single cells, or
• A thin section of tissue
• Usually stained to reveal structures of
  interest

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Image is NOT Everything
The image is the product of the interaction of
incident light with the object. Light must
INTERACT with the object Light interacts with
objects through wave-like and particle-like
properties.
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Magnification vs Resolution
Low Mag
More Mag
High Mag
Whoa Baby !
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Diffraction pattern of a saw blade
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Diffraction through a grating
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Diffraction through a grating
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Diffraction through a grating
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Effect of Oil
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Wavelength dependence
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Airy Disk Patterns
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Light MicroscopyLimit of Resolution
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Light MicroscopyLimit of Resolution
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Light MicroscopyLimit of Resolution
Limit of resolution (D) D

• wavelength of light
• n refractive index
• a angular aperture

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Light MicroscopyLimit of Resolution
Limit of resolution (D) D

• wavelength of light
• n refractive index
• a angular aperture

Numerical Aperture N.A.
N.A. 0.3 - 1.65
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Light MicroscopyLimit of Resolution
Limit of resolution (D) D

• wavelength of light
• n refractive index
• a angular aperture

70o
oil