# R = 1.72nm Resolution 200um slit width/Solux lamp spectrum

A project log for DAV5 V2.1 Spectrometer

The ZEN of simplicity Making the Complex...Seem Simple

David H Haffner Sr 01/12/2018 at 14:060 Comments

Ok, a lot is going on here, so 1st my latest plots using the new Ocean Optics slit I purchased from Ebay. 200um \$49.00 US. no too bad really, great service too. A quick recap on the calculations;

Rd - 1 X 200um X 1540 = 308

F = 532/308 = 1.72

Rd = 1.72nm

Resolution = 1.72nm

I'll verify this again through my 150mW laser but for now I have corrected a mistake on my part using the wrong slit width from before ( 100um, this was severly cutting my wavelength range and did not match my diffraction grating spacing.)

Here are the 1st set of plots:

Above Raw data captured on RSpec

Above Synthesized color spectrum representing my new wavelength range

Above actual Solux spectrum

Above Calibrated spectral plot

Above as you can clearly tell from this plot, the spectrum from the 100um slit has a far shorter wavelength range than the 200um spectrum. Notice the laws of physics at play here ( I get a longer wavelength range but give up a little resolution at certain wavelengths but make up for it in others, namely the full range of my dichrotic focal mirror 400 - 750nm.

Ok, in this plot I have included a scan from my 8-bit CCD detector, damn thing is full of bugs, need some help from people with far more experience in CCD's than me, but this was a good scan using a Tactical flashlight and the 200um slit width ( before I changed it to the cmos spectrometer.)

I cut off the CCD spectrum to fit this plot, the TCD1304 has 3647 pixels to play with the cmos has only 2048. The problem I'm having with the CCD is, exposure time, I can't get above 3ms and I can't figure out what to do about it, I have tried to re-calibrate the CCD, tweak to capture software and nothing works? I have also tried various filters, neutral grey, variable polarizing filters, the problem with filtering too much is you will eliminate some of the spectrum itself, so I am beside myself...

Is this because the CCD is 8 bit or does the capture software have to be more advanced in it's processing?