Name the formula for refractive index
n = sin(i)/sin(r)
How does an object appear, when looking throw a biconcave lense?
How does an object appear, when looking throw a biconvex lense?
What is the Gaussian common lense equation?
Name and describe forms of optical lense aberration
Coma: off-axis point sources appearing to have a tail (coma) like a comet
Astigmatism: eye with either lens or cornea egg-shaped -> distorted or blurred vision at any distance
Distortion: alteration original shape -> deviation from rectilinear projection to curved lines
Name the characteristics of an objective lense
How is the magnification of a micsroscope computed?
M Microscope = M Objective * M Eyepiece * M Intermediate Factor
What is the numerical aperture?
Amount of light, that can be captured by an objective: NA = n * sin(u)
n = refractive index
u = light cone angle
How is the resolution of a microcope computed?
resolution: minimal distance, by which two points can be seen seperated
lateral: d0 = λ / 2*NA; dmin = 0.6 λ/NA
axial: daxial = 3* dmin
What are transmitted light methods for contrast? Explain these methods.
bright field
light absorption and scattering
universal technic in light microscopy
used on sampes with colometric staining or good natural contrast
phase contrast
requires proper alignment bewtween phase plate and condenser annulus
high edge contrast on thin samples -> depth information
create height map -> pseudo 3D
differential interference contrast
light wave split into two differently polarized waves by Wollaston prism (-> shear) andrecombined behind object
strength defined by shear -> contrast can be adjusted
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