Sub-micron

The use of optimized microscope objectives, careful selection of the most appropriate laser wavelength, and specialized piezo-controlled mapping stages enables Raman microscopy to push towards the true optical limit of spatial resolution - the far field diffraction limit.  The use of piezo controlled stages offer ultra-fine sample stepping (down to 10 nm and below, depending on the stage) with high reproducibility.

In combination with the true confocal optics of the HORIBA Scientific Raman systems, it is possible to reliably analyse features with spatial resolution below 500 nm.

Not all samples will enable the spatial resolution to reach the theoretical sub-micron level.  In particular transparent samples can have significant and complex interaction between the laser and the sample which can reduce the achievable spatial resolution. However, with many samples Raman microscopy can be pushed towards its limits using relatively straight forward equipment and operation.

Polarised Raman mapping of 190 nm nanowire structures with a LabRAM system
Polarised Raman mapping of 190 nm nanowire structures with a LabRAM system.Data courtesy of D. Talaga (Université Bordeaux I, France) and F. Lagugné Labarthet (University of Western Ontario, Canada)
250 nm and 350 nm semiconductor features resolved through intensity mapping of the Si Raman peak with a LabRAM system
250 nm and 350 nm semiconductor features resolved through intensity mapping of the Si Raman peak with a LabRAM system Sample provided by ATMEL ROUSSET (Université Paul Cezanne, France)