The dependence of fanning noise on beam size in LiNbO3:Fe crystals with different thickness

We studied fanning noise in two LiNbO3:Fe crystals with different thickeness. Fanning noise just depends on the diameter of incident light on the front crystal face and have poor relation with the thickness of the crystals. We attributed it to that fanning noise is mainly caused by the amplification of the scattered light by the imperfections near the incident crystal face.