Testing the Labram's Spectrograph with Hamamatsu Detector
White-light spectrum with 633nm notch filter:
White-light spectrum with 633nm notch filter and 633nm laser line:
Note:
The 633nm peak always seems to be right on one side of the notch.
* Is that so part of it will always appear in the spectrum for calibration
purposes?
* The filter is old and contracting?
* The filter is not correctly aligned?
(later it was determined that the filter was only aligned for the reflected beam).
* The filter cutoff on the right is closer to the line allowing more of the Raman spectrum
on the low end to get through?
Spectral Artifact
650nm diode laser with 633nm He-Ne laser misaligned with the 633nm notch filter:
A very poor spectrum with unaligned optics.
A 650nm calibration laser diode was built into the Labram spectrograph
and appears to just shoot right at the grating without any attenuation.
The spectrum above was taken with this 650nm laser underpowered at about 3.4V
to prevent oversaturating the detector. I'm not sure how this laser
was used by Horiba. I don't think it was used to calibrate wavelength.
More likely it was used to align the optics in some manner...
[it is used to align the beam path inside the spectrograph backwards to the objective]