# flowfield must contain molecular species with an optical resonance wavelength that can be accessed by laser 
# temperature measurements typically require two laser sources 
# velocity measurements typically practical only for high Mach number flows (near sonic or supersonic) 
# signal-to-noise ratio often limited by detector shot-noise 
# fluorescence interferences from other species, especially from hydrocarbons in high pressure reacting flows 
# attenuation of laser sheet across flow field or reabsorption of fluorescence before it reaches detector can lead to systematic errors