  Infrared interferometry is currently in a rapid development phase, with new
instrumentation soon achieving milliarcsecond spatial resolutions for faint
sources and astrometry on the order of 10 microarcseconds. For jet studies in
particular, the next generation of instruments will bring us closer to the
event horizon of supermassive black holes such as Sgr A*, and the region where
jet launching must occur. But a new possibility to study microquasars in
general and jet physics in particular may also arise, using techniques similar
to those employed for finding faint exoplanets around stars. The compact,
steady jets observed in the hard state of X-ray binaries display a
flat/inverted spectrum from the lower radio wavelengths up through at least the
far-IR band. Somewhere above this band, a turnover is predicted where the jets
become optically thin, revealing a power-law spectrum. This break may have been
observed directly in GX339-4, but in most sources such a feature is likely
hidden under bright emission from the stellar companion or accretion disk
components. Detecting the exact location of this break would provide a new
constraint on our models of jet physics, since the break frequency is dependent
on the total power, as well as internal density and magnetic field.
Furthermore, knowing the break location combined with the spectral index of the
power-law would help constrain the amount of synchrotron emission contributed
by the jets to the X-ray bands. Along with a summary of some potential
observations requiring less optimal instrumental specifications, I will discuss
a technique which may enable us to discern the jet break, and the chances of
success based on theoretical models applied to some potential target sources.
