OPTICAL AND PIEZOELECTRIC SHEAR-FORCE CONTROLS DESIGNED FOR CRYOGENICENVIRONMENT

We describe two systems to control the tip-to-sample distance in near- field optical microscopes that are based on shear-force. Both of them are designed to work at low temperature. The first device follows a cl assical optical scheme but it is integrated in the microscope head. Th e second approach relies on a small piezocantilever to detect the fibe r motion. It is very compact and exhibits a high sensitivity to fiber motion. (C) 1998 Elsevier Science B.V. All rights reserved.