A PSTM working in the collection mode and based on an STM probe-sample regulation scheme has been developed. This original hybrid instrument for surface analysis uses apertureless metal-coated chemically etched optical. fibres. The use of an electronic tunnelling-based feedback loop significantly reduces tip-sample distance and leads to the collection of a high level near-field optical (NFO) signal. A simple amplified photodiode is thus used to perform optical signal acquisition and to draw electromagnetic field maps of sample surfaces. Experimental results on nanostructured gold surfaces are presented. (C) 2003 Elsevier B.V. All rights reserved.