Universal Light Modulator: A Breakthrough Laser Architecture for Precise Matter Control

• Researchers develop a new laser architecture named universal light modulator to probe and control matter. 
• It could be a turning point for all major photonic applications that require high power. 

Lasers are used for several purposes, including aligning materials, pointing out objects during a presentation, and by physicians for cosmetic and surgical procedures. Numerous things you see in your daily life are based on laser technologies, such as bar code scanner, optical disk drives, fiber optic, cutting and welding materials, laser lighting display in entertainment, and more.

Lasers have incredible capabilities to accurately drive, control and probe matter using different methodologies. Although they mostly function behind the curtains, lasers are the backbone of advanced science and technology. In 2018, the Nobel Prize in Physics was given to a revolutionary laser technology, Optical Tweezers, a technique to trap nanoparticles in between two laser beams.

Recently, researchers at the SLAC National Accelerator Laboratory and Stanford University developed a new laser architecture to probe and control matter. They are calling it the universal light modulator.

Laser Can Incorporate Sophisticated Structures

Since the laser emits light coherently, it can embody a much more complex structure than any other source of light in terms of intensity and electromagnetic distribution. For example, it could have unique three-dimensional intensity distributions (an optical strainer or a waffle cone), or cylindrical vector beams.

Due to these abilities, the universal light modulator has the potential to open new doors for advanced applications of photonics. At present, there aren’t many reliable methods available to produce complex light structures, thus exploiting the capacity for programming or engineering such structures is very difficult.

Reference: The Optical Society 

This is only done by external instruments like spatial light modulators used in projectors. However, these instruments come with peak power and average power limitations, and they can easily burst, without reaching out to applications that require significant power levels.

The new laser architecture evades this power limitation without affecting the ability to produce arbitrary light structures. The researchers developed an innovative functionality to engineer beams into the laser architecture itself. This fulfills the two main requirements: light structure and power scaling.

Beam shaping with new laser architecture | Greg Stewart / SLAC

They have used composite beamlets to build these programmable light pulses. You can think of it as a laser beam made of several honeycomb-like shorter beamlets, each of which can be controlled independently, despite the fact that they are all coherent with respect to each other.

They can ‘disclose’ information to each other, including their state and respective relationship. If all beamlets are synchronized, together, they can produce any structure.

Applications

The universal light modulator is extremely valuable within the ultrashort systems (in femtosecond timescales and even shorter): it can give rise to a whole new thinking about how lights with sophisticated structures can be used to drive technological endeavors. It could be a turning point for all major photonic applications that require high power, micro-nano machining, optical trapping, optical fiber telecom, and ultrafast proton sciences.

Researches are now trying to utilize these light source to control electron beams traveling at the light speed. This would help them create new kinds of X-ray and electron sources, and imprint the light structure onto the X-rays and electron.

Read: Practical 3D Display Generated By Holography and Light-Field Technology

Also, they plan to explore numerous parallel efforts. The very first thing is to integrate more beamlets and upgrade the modulator to much higher power. Second, they will examine how to convert femtosecond beamlets into other wavelengths using nonlinear conversion methods, which would produce structured light with hyperspectral composition and natural self-synchronicity, or with multi-color.