component are presented in the context of preservation of pulse duration from photoemission to sample. A magnetic condenser objective lens gives full control of the beam diameter at the sample and ensures that the angular velocity of the pulse is eliminated when the pulse traverses the plane of the sample, with magnifications in excess of $10^4$ possible. Comparison of the distribution at the sample and detector planes infers minimal spatial distortion. The minimum resolvable electric field is explored via time dependant electric fields superimposed on a nanometrically structured sample.

Results
=======

Photocathode Emission and Geometry 
-----------------------------------

As typical with NSMT sources, our fs-TEM consists of polycrystalline tungsten wire (125 $\mu$m radius) which tapers to an apex with a 50 nm radius of curvature and an opening angle of 10 degrees, as shown in figure 1 (a). Following the work of Hoffrogge et al [@Hoffrogge2014a], Paarmaan et al [@Paarmann2012] and Bormann et al [@Bormann2015], we incorporate an electrostatic suppressor, a 50 $\mu$m thick annulus with an inner diameter of 150 $\mu$m. The NSMT protrudes 100 $\mu$m from the suppressor surface, sufficient space for laser excitation. Grating coupled laser driven electron emission from a NSMT has also recently been demonstrated, relaxing the 