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:20260901T195855Z UID:c2280696-4693-4594-9832-295d723568cb SEQUENCE:1 CREATED:20260825T110010Z DESCRIPTION: Controlling the degrees of freedom of light is a topic of ext ensive experimental efforts. The characteristics of the light are determin ant in accessing the desired underlying physical phenomena. Structured lig ht emerged as a field of research dedicated to exploring and pushing the t ailoring possibilities for light sources.  A light spring (LS) is a compl ex form of structured light created through the coupling between the topol ogical charge and the frequency components of a pulsed beam. In its most r ecent generation scheme\, a circular diffractive axicon spectrally separat es the pulse\, which then receives different topological charges via phase modulations. Since these modulations are controlled with a spatial light modulator\, the beam can be tailored to present different forms of space-t ime coupling. In this work\, the generation of spatiotemporally coupled be ams with tunable properties is explored. Such beams open the possibility o f guiding light-matter interactions\, including the generation of new sour ces of radiation and platforms for synthetic motion studies.Initially\, a new 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 g ives way to controlling the interaction between light and matter in a new way. The sub- and superluminal regimes unlock the possibility of novel sou rces of radiation that could access different responses in light-matter in teraction systems\, as well as being a new platform for synthetic motion s tudies\, where beams with superluminal properties play a central role in u nlocking new interaction scenarios. Finally\, the control of the space-tim e beam spectral phase is implemented. This is an additional parameter that unlocks unprecedented control of light sources\, paving the way towards u ltrabroadband control of ultrafast pulses. LAST-MODIFIED:20260825T110010Z LOCATION:DF Seminar Room (2-8.3)\, 2nd floor of Physics Building/Online URL:http://df.vps.tecnico.ulisboa.pt/en/events/synthesis-of-tunable-space- time-beams-toward-structured-light-matter-interaction/ X-ALT-DESC;FMTTYPE=text/html:

Controlling the de grees of freedom of light is a topic of extensive experimental efforts. Th e characteristics of the light are determinant in accessing the desired un derlying physical phenomena. Structured light emerged as a field of resear ch dedicated to exploring and pushing the tailoring possibilities for ligh t sources.  A light spring (LS) is a complex form of structured light cre ated through the coupling between the topological charge and the frequency components of a pulsed beam.

In its most recent generation sche me\, a circular diffractive axicon spectrally separates the pulse\, which then receives different topological charges via phase modulations. Since t hese modulations are controlled with a spatial light modulator\, the beam can be tailored to present different forms of space-time coupling. In this work\, the generation of spatiotemporally coupled beams with tunable prop erties is explored. Such beams open the possibility of guiding light-matte r interactions\, including the generation of new sources of radiation and platforms for synthetic motion studies.

Initially\, a new tunable property of LS is defined: the orbital group vel ocity ( ). The  describes the velocity with which the apparent motion of the LS hotspot completes a full spin around its axis\, and it can be tailo red to achieve sub- and superluminal values. The tunability of the   in such a range gives way to controlling the interaction between light and ma tter in a new way.

The sub- and superluminal regimes unlock the possibility of novel sources of radiation that could access different resp onses in light-matter interaction systems\, as well as being a new platfor m for synthetic motion studies\, where beams with superluminal properties play a central role in unlocking new interaction scenarios. Finally\, the control of the space-time beam spectral phase is implemented. This is an a dditional parameter that unlocks unprecedented control of light sources\, paving the way towards ultrabroadband control of ultrafast pulses.

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