We want to buy a new laser Doppler vibrometer with a two wave mixing interferometer. We can choose between 1030 or 1064 nm SLM laser. Is there any difference in the photo refractive effect at these two wavelengths in GaAs?
There are low difference (a few percent) in the efficiency (signal modulation and SNR) of the photorefractive effect. 1064nm is the most common laser wavelength for using with GaAs crystal. but
1. Each crystal is individual, maybe the manufacturer of the vibrometer has established that with a 1030nm laser and using this crista GaAsl, the vibrometer is most effective. Therefore, it offers a more expensive laser.
2.On the other hand, choosing a laser between 1064 and 1030 may have no effect on the efficiency of the photorefractive effect. Then the choice is dictated by the need to filter or separate (a)the vibrometer radiation and the (b)radiation used in your experimental setup. So, for example, if your experimental setup uses a wavelength of 1064 nm, required to the choice of a 1030 nm laser in the vibrometer, it is possible to separate lasers radiations and remove mutual influence, reduce noise.
Thanks Timofey Aleksandrovich Efimov for the explanation. It seems that the anti reflective coating on the GaAs and all other components in the interferometer is for 1064 nm so I guess it’s safer to go with that...
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