BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:Synthesis of tunable space-time beams toward structured light-matt er interaction DTSTART:20260827T093000Z DTEND:20260827T120000Z DTSTAMP:20260901T153136Z UID:c2280696-4693-4594-9832-295d723568cb SEQUENCE:2 CREATED:20260825T110030Z DESCRIPTION:Controlling the degrees of freedom of light is a topic of exte nsive experimental efforts. The characteristics of the light are determina nt in accessing the desired underlying physical phenomena. Structured ligh t emerged as a field of research dedicated to exploring and pushing the ta iloring possibilities for light sources.  A light spring (LS) is a comple x form of structured light created through the coupling between the topolo gical charge and the frequency components of a pulsed beam. In its most re cent generation scheme\, a circular diffractive axicon spectrally separate s the pulse\, which then receives different topological charges via phase modulations. Since these modulations are controlled with a spatial light m odulator\, the beam can be tailored to present different forms of space-ti me coupling. In this work\, the generation of spatiotemporally coupled bea ms with tunable properties is explored. Such beams open the possibility of guiding light-matter interactions\, including the generation of new sourc es of radiation and platforms for synthetic motion studies.Initially\, a n ew tunable property of LS is defined: the orbital group velocity ( ). The  describes the velocity with which the apparent motion of the LS hotspot completes a full spin around its axis\, and it can be tailored to achieve sub- and superluminal values. The tunability of the   in such a range gi ves way to controlling the interaction between light and matter in a new w ay. The sub- and superluminal regimes unlock the possibility of novel sour ces of radiation that could access different responses in light-matter int eraction systems\, as well as being a new platform for synthetic motion st udies\, where beams with superluminal properties play a central role in un locking new interaction scenarios. Finally\, the control of the space-time beam spectral phase is implemented. This is an additional parameter that unlocks unprecedented control of light sources\, paving the way towards ul trabroadband control of ultrafast pulses. LAST-MODIFIED:20260825T110107Z LOCATION:DF Seminar Room (2-8.3)\, 2nd floor of Physics Building/Online URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/synthesis-of-tunable-space -time-beams-toward-structured-light-matter-interaction/ X-ALT-DESC;FMTTYPE=text/html:

Controlling the deg rees of freedom of light is a topic of extensive experimental efforts. The characteristics of the light are determinant in accessing the desired und erlying physical phenomena. Structured light emerged as a field of researc h dedicated to exploring and pushing the tailoring possibilities for light sources.  A light spring (LS) is a complex form of structured light crea ted through the coupling between the topological charge and the frequency components of a pulsed beam.

In its most recent generation schem e\, a circular diffractive axicon spectrally separates the pulse\, which t hen receives different topological charges via phase modulations. Since th ese modulations are controlled with a spatial light modulator\, the beam c an be tailored to present different forms of space-time coupling. In this work\, the generation of spatiotemporally coupled beams with tunable prope rties is explored. Such beams open the possibility of guiding light-matter interactions\, including the generation of new sources of radiation and p latforms for synthetic motion studies.

I nitially\, a new tunable property of LS is defined: the orbital group velo city ( ). The  describes the velocity with which the apparent motion of t he LS hotspot completes a full spin around its axis\, and it can be tailor ed to achieve sub- and superluminal values. The tunability of the   in s uch a range gives way to controlling the interaction between light and mat ter in a new way.

The sub- and superluminal regimes unlock the p ossibility of novel sources of radiation that could access different respo nses in light-matter interaction systems\, as well as being a new platform for synthetic motion studies\, where beams with superluminal properties p lay a central role in unlocking new interaction scenarios. Finally\, the c ontrol of the space-time beam spectral phase is implemented. This is an ad ditional parameter that unlocks unprecedented control of light sources\, p aving the way towards ultrabroadband control of ultrafast pulses.

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