Haim Suchowski, University of California, Berkeley
Conversion of one laser frequency to another is one of the oldest and most useful effects in nonlinear optics. However, in wavelength conversion devices, there is usually a trade-off between the efficiency of the conversion and the bandwidth over which the device functions. The introduction of adiabatic frequency conversion, a concept which utilizes an analogy between coherently excited two-level quantum system and the propagation of two electromagnetic waves in a nonlinear crystal, allowed the achievement of efficient scalable broadband frequency conversion.
The concept was applied successfully to the upconversion and downconversion of ultrashort pulses, where conversion of Ti:S oscillator pulses with near-100% efficiency for ultrabroadband spectrum has been achieved. The method is allowing the generation of high-energy, multi-octave-spanning IR pulsed sources in the 2-5 μm range and is expected to become a powerful seeding source for coherent wavelength multiplexers based on optical parametric amplifiers.
In my talk, I will review the mathematical background behind two level system and rapid adiabatic passage dynamics in frequency conversion realm. Then, I will show experimental demonstrations of the concept using tunable quasi-CW laser and ultrashort pulses, and discuss the robustness, tunability and scalability of the scheme. Last, I will review shortly, several follow-up works that deal with the extensions of the adiabatic dynamics into multi-level quantum systems, predicting new phenomena and concepts in frequency conversion. Also, the effort to explore adiabatic processes in the fully nonlinear dynamics regime of nonlinear optics will be presented.
