The laser architecture can create complex structures to probe and control the material

A new laser architecture called Universal Light Modulator, a new intriguing tool for probing and controlling matter, will be presented at the Optical Society (OSA) Laser Conference, which will be held November 4-8 in Boston. It was developed by senior investigator Sergio Carbajo and research associate Wei Liu, both of the SLAC National Accelerator Laboratory and Stanford University.

Coherent light, such as that emitted by a laser, can embody a much more complex and sophisticated structure, be it in the electromagnetic distribution or in the intensity distribution. "Some examples are cylindrical vector beams, or 3D funky intensity distributions that may look like, for example, a waffle cone or an optical filter," Carbajo said.

Because of these features, the universal light modulator is about to open new scientific and technological frontiers. The problem is that it is difficult to exploit the engineering or programming capacity of complex light structures, because there are not many reliable options for generating this structure, said Carbajo.

"Currently, this is done primarily by external devices such as the spatial light modulators commonly used in headlamps, but they all have medium and peak power limitations," said Carbajo. "These devices can burn easily and can not reach applications requiring high power levels."

The Carbajo group's work circumvents this power limitation while maintaining the ability to generate arbitrary light structures. They incorporated the ability to program beams into the laser architecture itself. This connects the best of both worlds: power scaling and light structure.

"Our programmable light pulses consist of composite beams," explained Carbajo. "Imagine a laser beam made up of many small, honeycomb-like bundles, each of which is independently controlled, although they are all consistent with one another." communicate with each other and "know each other" When all the beamlets are synchronized, they can collectively generate any structure.The problem is that this structure is made discrete by the number of beamlets. "

This programmable architecture is particularly important in the ultra-short (femtosecond and shorter) regime because it can inspire new ways of thinking light with complex structures capable of conducting scientific and technological endeavors. Potential new applications include fiber optic telecommunications, micro-nano-machining and additive manufacturing, optical trapping and ultra-fast proton science. "This can change the game in virtually all photonics applications that require high power," said Carbajo.

Researchers at SLAC National Accelerator Laboratory are interested in using these light sources to personalize and manipulate beams of electrons propagating at the speed of light. "In doing so, we can generate new types of electron and x-ray sources so we can print the structure of light on the electron or x-rays," he said. "These can then become advanced scientific instruments, because electron beams and X-rays would inherit the structure of optical photons."

Then the group wants to explore several parallel efforts. "The first obvious solution is to add more beams, which is required by a subset of potential applications," Carbajo said. "Many, however, need only a few beams, in our case we have 7 + 1 – seven in a bee nest, plus a master pilot." The second ramification is to carry our system at much higher powers, which also allows a third way: a better conversion of the fundamental femtosecond beams to other wavelengths using nonlinear conversion stages, which would create a structured light with a multicolored or hyperspectral composition and a natural synchronicity. "

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