GLOphotonics
Visionaries Stretching the Seams of Fibre Optics

Professor Fetah Benabid, like most scientists and researchers, is driven by an insatiable curiosity.

Even as the world celebrated major advancements in laser technology, Benabid—for a better part of two decades—remained focused on the needs that were not addressed by the existing laser technology/systems/etc.

For example, Benabid was quick to point out discrete gaps in several spectral regionsof laser systems, which hampered the efficacy of biomedical devices.The lack of laser emission in near-UV spectral regions (300-700nm) of the optic fibre meant a number of biomedical applications were not being utilised optimally. These included flow cytometry to detect single cells, DNA sequencing, forensic detection of latent fingerprints, and bio-agent devices used to detect pathogens or bio-toxins.

Not only did these applications warrant specific laser wavelengths (such as yellow), they required additional properties such as high spectral definition, a dynamic range of optical power, and temporal profile control. Besides their inability to address said requirements, laser systems utilised in such use cases were bulky, free space apparatuses that delivered a single laser line, sometimes with no spectral tunability at all. Furthermore, the optical fibres used in these devices were susceptible to optical damage, nonlinear optical response, and dispersion—all of which restricted their ability to deliver the needed high power and ultrashort pulses.

Benabid—convinced that existing laser technology could not cope with emerging biophotonic applications—kept seeking answers. The France-based researcher also questioned the fact that biologists, rather than laser specialists, were involved in the development of laser-based systems. The laser designs were too simple, he felt.

By 2002, Benabid and his team at the University of Bath made a breakthrough with the advent of a new type of optical fibre, the gas-filled Hollow-Core Photonic Crystal Fibre (HCPCF), and the subsequent development of its more integrated form, the photonic microcell (PMC). By combining optical fibre technology with the unique properties of gas-phase materials, Benabid discovered the process of confining gases and light together at micrometre-squared-scale mode areas that were nearly impossible to achieve with conventional laser systems.

The HCPCF technology was a timely innovation for laser beam delivery, especially for ultrashort pulse (USP) lasers utilised in laser surgeries, surface marking, and micromachining. Suddenly, biophotonic applications—in particular—received a shot in the arm as surgeons and biologists were able to direct the laser to any cell or body part in a safe, user-friendly manner. Critically, PMC-based laser systems could emit at any wavelength, and be assembled as tiny devices—needing limited maintenance or alignment—opening the doors forthe medical devices sector.

A New Day for Medical Device Developers

Such breakthroughs in laser technology have impacted modern medical devices to no end.

Benabid founded his company—GLOphotonics—to develop a host of highly innovative photonic components for medical machine manufacturers in areas of ophthalmology, surgery, and cancer treatment.

Proving to be a boon for biophotonic applications such as forensics and imaging, GLOphotonics’ proprietary GLO technology is also being actively used to develop next-gen devices for urology, biosurgery, and endoscopy.

The fact that we were the first to provide any colour and multi-line lasers is still appreciated by the medical industry

Again, the breakthrough would not have seen the light of day without Benabid questioning the efficacy of optic fibres more than 20 years ago. “Unlike conventional fibres where the cladding is solid, we have designed a fibre where the cladding is microstructured to specifically confine and guide light in a hollow channel,” says Benabid.

So, what is unique about guiding light this way?

“The hollow core can guide very high power lasers with extremely minimal energy loss, and transporting ultrashort pulse laser beams over long distances with no damage to its temporal integrity,” adds Benabid, who was awarded the Fresnel Prize in 2005 in recognition of his ground-breaking innovation.

Where traditional fibres propagate light using differences in the refractive index for reflection, the HCPCF— with its hollow cores surrounded by microstructures— rely on photonic bandgap (PBG) or on inhibited coupling (IC) mechanism to transmit high-energy light. To get a clearer idea of what these phenomena imply, it should be stated that when light propagates, it follows certain propagation modes. PBG guidance occurs when the core’s mode propagates in a space where the cladding is void of any mode, forbidding thus the light to escape from the core into the cladding. IC mechanism, on the other hand, originates from geometry in which core and cladding modes can exist together but are incompatible with each other to interact, resulting thus in light core-propagation without strongly escaping into the cladding. GLOphotonics’ team has engineered technology a family of HCPCFs that guide light on both mechanisms, giving rise to an entirely new wave of photonic fibres.

To summarise, GLOphotonics’ fibre offers a simpler and faster way to deliver laser light from the source to the desired destination without any loss of power.

Of course, GLO’s PMC technology would not be possible without the other building block, the innovative process of filling the photonic fibre with ionised gases, molecular gases, or atomic vapours to achieve desired photonic functionalities. The abundance of free moving gaseous molecules and atoms not only makes the fibre light and manufacturing less cumbersome but also improves the versatility of fibre usage (in spectroscopy, gas sensing and lasers). Particularly in the case of medical technology, GLOphotonics’ fibres shine through in flying colours, burning away afflicted cells with high energy lasers. “The ultra-short, high power laser pulses ablate the cells without causing the fibre material to heat up or cause damage to surrounding cells,” explains Benabid.

Customising Devices to Reach New Wavelengths

Speaking of medical technology, it is critical to highlight that GLO enables the development of customised devices needed to operate at specific wavelengths to perform medical procedures.

One such use case includes the work GLOphotonics is doing with regard to the treatment of a variety of blood vessel disorders such as removal of unwanted leg veins and facial capillaries. Another noteworthy use case where GLO technology has proven ideal, is next generation machines for ophthalmology surgery.

“Unlike conventional fibres where the cladding is solid, we have designed a fibre where the cladding is microstructured to specifically confine and guide light in a hollow channel”

So, what sets GLO technology apart from its solid core counterparts in the market? Solid core fibres are notorious for getting damaged too quickly when high energy light propagates through them. GLO’s PMC not only remains unscathed during propagation, but it also transmits the light with infinitesimal energy loss. “Even if there is no need for high energy light, solid core fibres will still distort the temporal integrity of the pulse due to nonlinearity effects such as Raman and the Kerr,” stresses Benabid. The technology of the PMC allows users to control the pressure of the gas and evacuate air to be rid of the issues of non-linearity. Furthermore, eliminating non-linearity allows pulses to be compressed down to a tenth of a femtosecond—facilitates precise heating, another factor that makes GLO’s PMC technology invaluable to the world of medicine.

Surging Ahead with Momentum

There is little doubt that a bright future awaits GLOphotonics, a company that continues to earn the acclaim and faith of Europe’s photonics industry. Over the last seven months, the startup has received Series A funding from global high-tech companies such as DMG Mori Seiki Co and TRUMPF Lasertechnik GmbH + Co. KG. These investments will allow GLOphotonics to enter the next phase of its business, recruit top talent, complete a state-of-the-art production facility, and address newer industrial markets.

One such emerging application is bioimaging, a complex field that requires the delivery of specific light (in multiple lines) to visualise biological activity within a timeframe. If there is a technology equipped to handle the application, it is GLOphotonics. After all, its PMC technology’s ability to create multi-laser lines was tested by the National Institute of Health (NIH), an achievement that Benabid is still proud of. “The fact that we were the first to provide any colour and multi-line lasers is still appreciated by the medical industry,” he says.

While GLOphotonics does not have direct access to the end-user, it will continue to collaborate with major manufacturers and system integrators across the world to bolster its global network. The company is also committed to providing samples, application notes, and reference designs to its target markets to help them integrate GLO components into their new products. Working closely with its partners, GLO will also generate application examples to highlight the features and benefits of its proprietary PMC technology.

All the success not withstanding, Benabid takes pride in the fact that GLOphotonics and its solutions’ ingenuity prove beyond helpful to institutions looking to battle cancer. As a matter of fact, GLOphotonics’ technology has also been used by NASA in their space expeditions!

Its technology is changing the way the world views optical fibre technology—from simple fibres for communications to sophisticated photonic crystal fibre technology that saves lives.