Project: Sequential parametric amplification: quantum technology with multimode light

Acronym SPARQL
Duration 01/04/2022 - 31/03/2025
Project Topic Parametric amplification plays an important role in many quantum technologies. A parametric amplifier is as indispensable as an operational amplifier in classical electronics. The very noise of a parametric amplifier is squeezed vacuum, the workhorse of quantum optics. By placing two parametric amplifiers in sequence one obtains the so-called SU(1,1) interferometer, theoretically proposed decades ago but realized in experiment only recently. This is an example of an active interferometer; it outperforms conventional passive interferometers and provides new topologies suitable for many quantum applications. Confirmed by recent experiments, sequential parametric amplification provides: - phase sensitivity beyond the shot-noise limit; - possibility of ultra-broadband (up to 120THz) optical homodyne detection by using the second amplifier as an optical homodyne device; - tolerance to detection loss provided that the second amplifier gain is sufficiently high. SPARQL will develop multimode sequential parametric amplification and use it for current needs of quantum technology. We will consider parametric amplification of both spatial/angular modes and temporal/frequency modes. As a result, we will implement the following techniques, with tolerance to loss: - squeezing-enhanced imaging and microscopy; - squeezing-enhanced Raman spectroscopy and wide-field microscopy, with orders of magnitude speedup due to the multimode structure; - squeezing-enhanced frequency-multimode quantum key distribution. Moreover, we will address a new area of non-Gaussian frequency-multimode quantum sensing to overcome limits of squeezed-enhanced sensing, spectroscopy and microscopy. SPARQL will contribute in three areas of the call and all four major pillars of quantum technology. It primarily relates to quantum metrology, sensing and imaging, namely light-based calibration and measurement, because it considers the squeezing-enhanced measurement of phase shifts, small absorption values, and quadrature noise. Compared to existing methods of sub-shot-noise measurements, SPARQL enables two important advances: multimode measurements and loss tolerance. The use of multiple frequency modes enables spectral sensing/spectroscopy and the use of multiple spatial modes is a platform for quantum imaging. SPARQL also addresses quantum information with continuous variables. The methods of multimode homodyne detection, developed in the project, will allow enhanced quantum communication as multimode squeezed-states are used for quantum key distribution. SPARQL involves the preparation and measurement of multimode non-Gaussian entangled states, which are the promising element of distributed quantum sensing, imaging, spectroscopy and microscopy.
Network QuantERA II
Call QuantERA II Call 2021

Project partner

Number Name Role Country
1 Max-Planck Institute for the Science of Light Coordinator Germany
2 Laboratoire Kastler Brossel Partner France
3 Bar-Ilan University Partner Israel
4 Raicol Crystals Ltd Partner Israel
5 Univerzita Palackeho v Olomouci Partner Czech Republic