The group of Avi Pe'er Leads advanced experimental research in precision measurement and control, quantum optics and laser physics. The group explores new schemes for measurement and control of quantum matter and quantum light. Specifically, we pursue new methods to visualize and manipulate fast vibrational dynamics in molecules, as well as concepts to measure optical phase with resolution beyond the classical (shot noise) limit. The key experimental tools are novel light sources that combine both ultra-long coherence (up to 1s coherence time) and ultrabroad emission spectrum (of order 100 THz), and that are divided into two classes – Ultrafast frequency comb sources and sources of ultra-broadband quantum-correlated (squeezed) light.

 

The ultrafast frequency comb - A phase-stabilized ultrafast mode-locked laser - produces a comb structure in frequency with very sharp teeth (~1Hz, state of the art) at precisely known, equi-spaced frequencies, over a very broad spectrum. pulseIt forms a perfect ruler in the optical frequency domain, against which other optical frequencies can be measured and referenced. While the frequency properties of the comb led to breakthroughs in precision spectroscopy and atomic clocks, the time domain properties are equally important. With a phase coherent train of ultrashort pulses, it is possible now to perform for the first time in the optical domain fast, yet very precise manipulations on atomic and molecular systems in a similar manner to what was done in NMR for years on spin systems with RF fields. Our lab develops novel frequency comb sources with tailored spectra or based on new gain media, as well as new applications of direct frequency comb measurement for visualization of fast vibrational dynamics in molecules.

 

The other source is based on Broadband quantum-correlated fields, such as those emitted by parametric down conversion or by four waves mixing. On the classical level, such sources emit a pair of broadband fields (signal and idler) that are totally incoherent, demonstrating properties of white noise, yet perfect phase and amplitude correlation exists between them, leading to narrowband two-photon coherence of the combined field. Quantum mechanically, the parametric nonlinear process converts pump photons, into pairs of energy quanta (signal photon and idler photon) that are highly entangled in time-energy. In our lab, we generate broadband correlated fields and measure their correlation properties at various power levels, from the low-power quantum regime of single photon pairs up to the highly stimulated, semi-classical regime of many photons. We explore applications of such sources for precision measurement beyond the classical limits, as well as to to coherent Raman spectroscopy and to spread spectrum optical communication.

 

Current research directions in the group are: