  We report on an asymmetric high energy dual optical parametric amplifier
(OPA) which is capable of having either the idlers, signals, or depleted pumps,
relatively phase locked at commensurate or incommensurate wavelengths. Idlers
and signals can be locked on the order of 200 mrad rms or better, corresponding
to a 212 as jitter at $\lambda$=2$\mu$m. The high energy arm of the OPA outputs
a combined 3.5 mJ of signal and idler, while the low energy arm outputs 1.5 mJ,
with the entire system being pumped with a 1 kHz, 18 mJ Ti:Sapphire laser. Both
arms are independently tunable from 1080 nm-2600 nm. The combination of
relative phase locking, high output power and peak intensity, and large
tunability makes our OPA an ideal tool for use in difference frequency
generation (DFG) in the strong pump regime, and for high peak field waveform
synthesis in the near-infrared. To demonstrate this ability we generate
terahertz radiation through two color waveform synthesis in air plasma and show
the influence of the relative phase on the generated terahertz intensity. The
ability to phase lock multiple incommensurate wavelengths at high energies
opens the door to a multitude of possibilities of strong pump DFG and waveform
synthesis.
