Jon Baker wrote:

>I am working on a similar but slightly more complex project at the moment
>which needs to detect 4 different wavelengths of light emitted from a sample
>luminescing. The amplitude ( brightness??) of the light at each frequency
>must be measured independently so I can draw 4 graphs- each frequency
>corresponds to a particular molecule and the graph is to show the
>concentrations ( brightness ) with time of each. I am positive this can't be
>done with filters over photo detecetors becuase the number of photons I need
>to detect is so small it would be absorbed into the filter. What would be
>ideal is a several photodetectors each of which is sensitive to a
>(different) narrow band of wavelengths. Does anyone have any pointers where
>I could look for such specific devices?
>

Alternately, why not use a prism to separate the light frequencies to
focus on four separate spots and position four photo multipliers, one at
each spot to measure the separate colors?  It's an "old tech" solution
but a good one.

- Karen

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