Fluorescence Microscopy Flashcards
What are the 2 types of Aberration Correction?
Chromatic Aberration & Spherical Aberration
What is Chromatic Aberration?
Colours bend light to different degrees. There are lenses that correct for this so that the wavelengths are at the same focus. This process is chromatic aberration.
What is Spherical Aberration?
Light that hits at the edge of a lens bends more than light that hits at the centre of the lens. Spherical aberration is the process of correction so that light is in the same focus.
What is Numerical Aperture?
How much light you can gather, and therefore how much detail you can see.
Which medium is commonly used for its high refractive index?
Oil. It’s refractive index is close to glass. This means the light bends less (as there is less mismatch), and more light can reach the objective.
What is resolution limit?
Minimum distance 2 points can be told apart.
What is Stoke’s Shift?
Emitted photons have less energy because of vibrational relaxation (heat). Returns to higher level in ground state. This results in fluorescence.
In the basic principle of epi-fluorescence, how many filters are there? What are they called? What do they do?
There are 2 filters. They are called the excitation filter and emission filter. The excitation filter blocks long wavelengths. The emission filter blocks short wavelengths.
What is the role of the dichronic mirror?
The excitation filter lets through short wavelengths. These are reflected off of the mirror, to pass through the objective and reach the specimen. Longwavelengths then travel back towards the mirror, which lets the long wavelengths through (instead of reflecting), to reach the emission filter, lens and camera.
