Construction of System to Measure Scattered Harmonics from Electrons in a Laser Focus

We are constructing an apparatus to measure the harmonic emission from electrons in a high-intensity laser focus. We use spatial, temporal, and spectral filtering techniques to extract the single-photon-level signal from the much stronger background scattered light.  This system is designed to study electron dynamics in a high-intensity focus, and gather information about the detailed vector-field distribution in the laser focus.  We present details of the construction of this system and its current status.