Research

The primary theme of our research is to reliably map quantum information from light into matter, and from matter into light. We’re currently focused on studying the physics of collective spin excitations in atomic Rubidium. By combining previously demonstrated processes with an optical resonator, we are hoping to enhancing the interaction strength to the point where single quanta of light can be reliably mapped into and out of an ensemble of matter.

We are a relatively new lab - we’ve moved into the lab space in 2021 and as such, we are doing a lot of building of electronic, optical and mechanical parts. This is a wonderful time for student workers as you really learn by doing and building lab equipment by yourself will give you a crash course in engineering that you’ll carry with you into your career.

We presently have several main forks to our research. Within each of these, there are several sub-projects (see “projects” page)

Laser Stabilization: Our research requires highly coordinated behavior across several different systems: atoms, lasers, and optical cavities. We are developing a locking scheme in which an optical resonator is locked to a laser, which is phase locked to another laser, which is locked to the resonant frequency of atomic Rubidium. This complex locking scheme involves several disparate steps: The optical resonator is a Fabry-Perot cavity, which employs a Pound-Drever-Hall Lock (PDH) so that its mirror spacing is always integer multiple of the laser wavelength, ΔL = mλ/2 of a laser. This laser is phase locked via an Optical Phase Locked Loop (OPLL) so that their beat note is precisely equal to the hyperfine ground state splitting of Rb atoms. Finally, this laser is in turn frequency locked to the resonant wavelength of Rubidium via a Dichroic Atomic Vapour Laser Lock (DAVLL). This system will enable us to perform cavity enhanced interactions between Rb atoms and photonic quantum information.

Cavity Enhanced Source of Quantum Light: We’re exploring a method of engineering the quantum state of light using a process known as “Four-Wave Mixing” in Rubidium Vapour. In this process, a strong pump beam creates pairs of photons in distinct channels. By performing selective measurement on one of these channels we can “chisel-out” an arbitrary state on the adjacent channel. Some of the previous work by Andrew and Collaborators has shown this to work in principle, but fairly strong lasers were required for a measurable effect. By combining this source with an optical cavity we aim to demonstrate large optical a non-linearity with meager light levels.

Giant Optical Nonlinearities : One of the selling points of light as a means of transporting quantum information is that it travels over great distances, at great speeds, without interacting with other light. This lack of photon-photon interaction turns out to be a double-edged sword - occasionally you do want light to interact with other light. For example a photon-photon gate could conditionally induce a phase shift on a second photon, only if it is present, forming the basis of a quantum C-Phase gate. One such technique to accomplish this is Electromangnetically Induced Transparency, in which a very small shift in frequency leads to a giant shift in phase. By enhancing the field associated with a single photon (see Cavity Enhanced Source of Quantum Light above) we aim to maximize the phase shift imparted by a single photon.