With respect to the DIY Raman spectrometer we will proceed slowly.
You will find excellent internet reports by people who have built their own Raman
spectrometers everywhere in the internet. But nevertheless the DIY Raman remains a challenge.
The individual situation might be very different because of:
-- Different demands (measurement range, sensitivity, precision, resolution)
-- Different microscopes to be used as a basis for the DIY construction
-- Different budgets
-- Locally different access to filters, laser modules and spectrometer modules
-- Last but not least: different safety requirements (laser safety, e.g. in schools!)
As a consequence we are going to present a rather simple, almost generic construction plan.
It is essential to understand the basic principle first and to become creative second.
In its simplest form a Raman microscope spectrometer can be described as follows:
>> Strong laser light, precisely focused on a tiny object area
>> 99,9 % of the light is not absorbed by the sample. Only a very small fraction of the photons is coming back loaded with Raman information
>> After filtering out the unchanged (useless) laser light by means of a so-called long-pass filter the Raman signals are coming out
>> These have to be wavelength-splitted by means of a classical light spectrometer
>> and in the end there might be a spectrum, hopefully!
Compared to e.g. classical infrared spectroscopy the "Bauplan" is rather simple
and is consisting of relatively few components which are:
Solid-state laser (strong laser pointer) - focusing optics - sample holder - laser rejection filter - focusing optics - VIS spectrometer module.
More details will follow.