How to uselight microscope

MILLAR, Neil – WHITE, Ian. Microscopy [online]. The last revision 2004-06-18, [cit. 2012-12-09]. .

Live cells generally lack sufficient contrast to be studied successfully, internal structures of the cell are colourless and transparent. The common way is to increase contrast by different structures with selective dyes, but it often involves killing and fixing the sample.

What is amicroscope

The light from stars (other than the Sun) can be considered collimated for almost any purpose, because they are so far away they have almost no angular size.

The waves that associate the electrons has smaller wavelength. Then we can use electrons using an electron microscope. Electron microscopes can be used to visualise viruses, molecules and even individual atoms.

The word "collimate" comes from the Latin verb collimare, which originated in a misreading of collineare, "to direct in a straight line".[1]

Light microscope

In the 1870s, Ernst Abbe explained why the resolution of a microscope is limited. Since the microscope uses visible light and visible light has a set range of wavelengths. The microscope can't produce the image of an object that is smaller than the length of the light wave. Any object that’s less than half the wavelength of the microscope’s illumination source is not visible under that microscope. Light microscopes use visible light.

The University of Waikato. Magnification and resolution [online]. [cit. 2012-12-09]. .

Collimated light is light whose rays are parallel. This light spreads slowly as it travels. The word collimated is related to collinear, because all the rays in collimated light line up with each other.

Optical microscopemagnification

Optical Microscope uses system of lenses and visible light to sharply magnify small detailed samples which is projected directly to the eye.

Electronmicroscope

A perfect parabolic mirror will bring parallel rays to a focus at a single point. Conversely, a point source at the focus of a parabolic mirror will produce a beam of collimated light. Since the source needs to be small, such an optical system cannot produce much optical power. Spherical mirrors are easier to make than parabolic mirrors and they are often used to produce approximately collimated light. Many types of lenses can also produce collimated light from point-like sources.

Perfectly collimated light would not spread out with distance at all. No real light is perfectly collimated. Real light will spread a little as it travels. Diffraction prevents anyone from creating a perfectly collimated beam.

Laser light from crystal and some gas lasers is highly collimated because it is formed in an optical cavity between two parallel mirrors, in addition to being coherent. The divergence of high-quality laser beams is commonly less than 1 milliradian, and can be much less for large-diameter beams. Laser diodes emit less collimated light due to their short cavity, and therefore higher collimation requires a collimating lens.

These limitations have overcome to some extent by specific microscopy techniques that can non-invasively increase the contrast of the image. In general, these techniques make use of differences in the refractive index of cell structures.