Speaker
Chetan Deshmukh
(University of Calgary)
Description
Many applications of quantum information processing benefit from, or even require, the possibility to detect the number of photons in a given signal pulse without destroying the photons nor the encoded quantum state. We propose and show first steps towards the implementation of such a Quantum Non-Demolition (QND) measurement for time-bin qubits. To implement this measurement, we first store a ‘probe’ pulse in a cryogenically cooled Tm:LiNbO3 waveguide using an Atomic Frequency Comb (AFC) quantum memory protocol [1]. We then send a ‘signal’ pulse comprised of two temporal modes off-resonantly with the AFC through a previously prepared transparency window. The off-resonant interaction between the propagating signal and the thulium ions, onto which the probe pulse was mapped, results in the atomic state acquiring a phase-shift. This phase shift is imprinted onto the recalled probe pulse and can be determined using an interferometric measurement. The magnitude of this phase-shift depends on the signal pulse's energy, and detuning w.r.t to the probe pulse. Hence, knowing the phase-shift, we can determine the intensity or the number of photons in the signal pulse.
[1] E. Saglamyurek et al, … Nature 2011
Primary author
Chetan Deshmukh
(University of Calgary)
Co-authors
Prof.
Christoph Simon
(Collaborating professor)
Dr
Daniel Oblak
(Post-Doc)
Dr
Khabat Heshami
(Post-doc)
Mr
Neil Sinclair
(PhD student)
Prof.
Wolfgang Tittel
(Advising professor)
