The Basic Monochromator 
This image is strictly a 3D block diagram of a much more
complicated illumination system. Breaking it all down should make the overall
system easier to understand. The two black bars in the diagram represent a
precision slit, and the three layers of blue, in two shades represent two different lens
grades of piano glass. The point here is to define the concept behind using the
very low lens grade glass, light blue, and the very high lens grade glass. It will
produce a fairly coherent beam of light. The image shows the glass thickness much
larger than they ought to be. The low lens grade shouldn't be more than 1mm.
The high lens grade would be serving two purposes, refraction, and mechanical rigidity.
The black cylinder is the optically sealed cavity that contains a xenon and neon
flash bulbs.
Assuming that you been to the previous link, looking at the
deflection angles involved shows that a row of fibers will produce a much more coherent
apparently flat beam. The edge to edge deflection plane through the low lens grade
of glass width is significantly wider. This diffusion of light would be the
distributed from the source based upon higth of the deflection plane. Keeping the
source of light in an optically sealed container prevents light contamination from the
source{bulbs} reaching the output of the prism. Continuing to keep the light
focused moving it away from the output by using mirrors and consitantly eliminating the
contamination will produce a much more specific wavelength of light as the components
are accumulated and the monochromator assembled in the course of the following web
pages.
The best proof that spectrum specific imaging is possible can be
found here by the repeated image on film of the compact flourescent bulb through a prism
viewed through a primitive spectroscope. Now, it is possible to use only the
spectrum associated with a given spectrum of light as a light source using beam
splitting techniques, and know if the lens arrangement is correct a spectrum specific
image can be produced. If we were to use the radio table of elements the fingerprint of
each element would define what is lighting the bulb, the glass is made of, and what is
in the air around it. This could enable biologists, and virologists to watch a cells
internal chemistry at work. But, there are a list of problems proposed by attempting to
capture images that could be predicted by certian lens filter problems found using
monochromatic light sources. For example passive filters verses the transmissive
filters using only black and white film. A passive filter will block completely certian
colors, or wavelengths of light whereas, the transmissive filter will convert one
wavelength to another. This would produce a black spot, and a white spot on film even
though the wavelenght of light entering the transmissive filter is not the same as that
exiting the ability to define that anything is infront of the light source could become
almost impossible. Under the microscope this will hold equally as true, and certian
molecules, sugars, starches etc. will be transmissive, or passive in the cell, and
nearly invisible to white light.
The following image includes optically sealed cavity, and prism used for breaking the light down into its individual wavelengths. A cylidrical lens will follow the prism, and broaden the spread of the light. The next section will cover the gang flash monochromators and how artificial color allows for chemical reaction tracking under the microscope. |
