2.3 Compound Microscopes as Scientific Instruments

Figure 2.8: An Early Compound Microscope by Carl Zeiss

During the 18^th century, chromatic aberrations were reduced in compound microscopes. However, it was only in 1930 that a way to reduce spherical aberration was found.

\[\begin{equation*} \text{Resolution} = \frac{0.61 \cdot \lambda}{NA} \end{equation*}\]

In 1873, Ernst Abbe developed his theory of microscopes and came up with the above formula.

2.3.1 Developments in Microscopes in the Past Century

Several types of microscopy have been developed in the past, namely:

1. Phase contrast microscopes

   

   Figure 2.9: Comparison Betweeen Bright Field and Phase Contrast Microscopy on Live Cells

2. Confocal microscopes (1961)

   

   Figure 2.10: Confocal Microscopy Being Used to Visualize Organelles

3. Single molecule imaging (1990s)

   

   Figure 2.11: Single Molecule Imaging on a Sample

4. Super-resolution microscopes (2006)

   

   Figure 2.12: Super-Resolution Microscopy on Microtubules

   The following men were also awarded the Nobel prize for their invention of super-resolution microscopy: Eric Betzig, Stefen Hall, and William Moerner.