Well I've been wrong before and I was wrong this time too, I re-examined the original paper that I sited for this project because I felt something wasn't quite right, and I wasn't too far off the mark. What I missed was in their initial setup they have a pinhole diaphram as a beam shaper before the laser strikes the sample, hence forgoing a "real" laser collimator, this actually is still fine (although it would of been better if they would have given the dimensions for the pinhole size, but I figured it out through trial and error...)
Dimensions are: 0.6mm/0.02" in diameter
This is the raw jpeg image, zoomed by 50X to show the actual laser point (TEM00)
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Looks awesome huh? Almost like the Sun, if U look close you can see a finger print on the diffraction grating to the far left...oops
Below is the actual spectrum as seen by the detector
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Below is the plot, the FWHM value (full width half maximum,) of the beam is 1.5nm!
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The DSLR camera settings were as follows:
F-stop @ 10
Exposure time @ 1/30 sec
ISO @ 7200
Exposure bias @ -5 step
35mm focal length
I am incorporating the pinhole mount to fit into the laser guide component block for the Raman probe and will have a proper build log when I have ALL components printed as I keep re-designing out of necessity.
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