Activities

Research Fields

I study the interaction of light with matter.

More specifically, my interest is in the development and application of strongly correlated light, which are the building blocks of technological applications such as quantum spectroscopy, novel sources of quantum light (lying beyond the classical description).

Emitters of quantum light

The concept of quantum light rises from the counterposition to the classical light. While the latter is well described by the classical theory of electromagnetism, i.e.,  the theory formalized by Maxwell, the former is not. In fact, quantum light has properties that are not predicted and cannot be described with the classical theory. Perhaps the most important of them is the capability of quantum light to display the so-called antibunching, which is related to the way in which photons in a beam are separated in time. A laser (which is a classical source of light) emits its photons in a random way, which means that once a photon is emitted, we have no idea when the next one might come: it could follow immediately, or it can be emitted a very long time afterward. Such a random behaviour is well described through a Poisson distribution of the emission times. On the other hand, sources of quantum light are able to emit their photons in a more organized way, namely, the emission of a photon gives us some information about the time at which the next photon will be emitted. Thus, when the photons emitted by a quantum source are more separated from each other than they would if they had been emitted by a laser, we say that these photons are antibunched.

Using quantum emitters to excite optical targets opens an infinitude of possibilities and new behaviors, as the excitation itself brings to the target a quantumness, which otherwise had to rise from the internal dynamics of the driven object. Furthermore, the correlations between the photons (the way in which the photons are organized in time) can be exploited to unveil the internal structure of the driven system, thus allowing the development of quantum spectroscopic techniques.

Polaritons

Exciton-polaritons (or simply polaritons) are pseudo-particles arising from the strong coupling between a photon and an exciton (an electron-hole pair), which live confined in two dimensions inside a semiconductor microcavity. Polaritons inherit properties from their constituent particles, such as the lightweight from its photonic component and the interacting character from the excitonic counterpart. As such, polaritons can be thought of as interacting photons on which quantum information can be encoded, and which can be transported along great distances. Besides, their high-efficiency operation takes place in the micrometer scale, which place them as an interesting platform to develop quantum technologies.