The most important exhibition was certainly the Innovation Village at Photonics Europe in April 2010 in Brussels. I reported with photos on my blog.
In February 2009, Terahertz Systems and Industrial Applications was an opportunity for exhibiting a poster with terahertz images at the Royal Society.
A click on the poster gives you a larger version.
Previously, my first exhibition was part of the third conference on Nano-Molecular Analysis for Emerging Technologies at NPL in November 2008. I produced posters which I show on my blog.
But of course, the biggest event, with my own stand, was UK @ CERN in 2006.