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**Length and dimensional quantities

Research and development activities covering length and dimensional quantities are divided up into maintaining updated references and development studies.

In 2006, the main studies were focusing on :

Metrology traceability using comb technology

The aim of this study is to implement a device enabling to directly measure any wavelength ranging from 500 nm to 1 100 nm with relative uncertainty in the magnitude or some 10-12.

The device that is being developed is based on one Ti :Sa comb laser pumped at around 532 nm (figure 1) followed by one photonic crystal fibre so that the frequency comb can cover one octave.

Fig. 1. - Comb system under development at the LNE-INM
Fig. 1. - Comb system under development at the LNE-INM

Dimensional nanometrology

The LNE's dimensional metrology activity is concentrating on the development of a measurement capability for artefacts originating from the nanotechnologies.

The cornerstone of this activity under development is the conjunction of :

High accuracy three-dimensional positioning system

The LNE is constructing one three-dimensional positioning system (figure 2) that has a measurement range :

Fig. 2. - Positioning system within its environment
Fig. 2. - Positioning system within its environment

This device implements the principle of the dissociated metrology structure that is applied to the angular plate, national reference for angle.

Atomic Force Microscope (AFM)

The sensor selected to scan the topography of the samples is an Atomic Force Microscope . In order to ensure enhanced control over the instrument (more particularly regarding the measurements traceability aspects), the LNE has decided to develop an in-house AFM microscope (figure 3).

Fig. 3. -  View of the AFM probe on its based used for coupling the 3D positioning system.
Fig. 3. - View of the AFM probe on its based used for coupling the 3D positioning system.