What is the requirements from an optical lab in terms of darkness I am characterizing an optical lab and would like to know therefore what are the requirement from a standard optical lab in terms of ambient luminescence. In other words how dark should an optical lab be. The lab I am talking about should fit for experiments of photoluminescence and Raman spectroscopy.
 A: As @Carl mentioned in the comment (with a bit more elaboration), you need to determine this by a review of the literature and experimentally:


*

*determine what the expected signal levels for your experiment will be, this can be achieved in the crucial literature review of previous similar work.  This will effectively set a theoretical baseline of what values to expect.  This prior research will also provide an indication of the expected range of measurements.

*Determine what level of SNR (signal to noise ratio) would be acceptable for your experiment. This could also be determined by research also.

*Measure the current light levels that currently exist when you have the experiment setup. Either do a sensitivity analysis and/or some preliminary testing to determine the SNR that occurs within your measurements - from then, adjust the light level accordingly if possible, or determine a correction for the ambient light (see the 1st example reference below).


Some research that may be relevant (as I am not privy to the details of your research):


*

*In-situ photoluminescence measurements during MOVPE growth of GaN
and InGaN MQW structures (Prall et al. 2015), explain the
experimental procedures that were



employed to reduce unwanted light from other sources (thermal origin, ambient light)



*Selecting an Excitation Wavelength for Raman Spectroscopy
(Tuschel, 2016) - discusses a method how to achieve an optimal SNR.

*A study in the European Journal of Mineralogy, "Restricted access
Gated Raman spectroscopy: potential for fundamental and applied
mineralogy" (Gaft and Nagli, 2009) is about how the authors



demonstrate how a pulsed UV laser and time-resolved detection methods allow discrimination of Raman signals from strong luminescence background light

