Calibre interview: Sean Tipper, CTO at Sentinel Photonics

Lasers are proliferating across the battlefield, and with them the threats to personnel and equipment. Calibre Defence met with Sean Tipper, the CTO of Sentinel Photonics to learn more about the ways they are being used, and what the company can do about them. 

In 2015, as the first phase of the war in Ukraine came to an end, and “separatist forces” took up defensive positions across from the Armed Forces of Ukraine in the Donbass region, Russia began deploying new weapons and technologies to test them. Periodically, the operational security of the troops involved would be lax enough that Western analysts would get a glimpse into what was going on. On one occasion, a team of Spetsnaz, well-equipped with DJI Mavics, anti-drone guns, and commercially available Western marksman rifles were observed making their way into Separatist trenches. Their equipment gave some indication into how sniping had changed in the “anti-terrorist operation,” with drones playing an important role for both finding targets, and finding snipers. 

When they occurred, these sightings were fairly well-reported on through social media and defence news outlets, but the use of other weapons less so. In 2016, Ukrainian border guards deployed to a checkpoint near the city of Marinka, which is close to Donetsk city. From their position they looked West, towards Russian-held territory, two with a monocular and one with binoculars. Within a short space of time, they all report seeing a flash of light that left their eyes severely damaged. “The medics that analysed the traumas say that such injuries are caused by lasers,” the Kyiv Post quoted a spokesman for the Border Service as saying in 2018. The two guards using a monocular suffered burns to just one eye, the unfortunate guard using binoculars suffered burns in both. 

The border guards were not alone, and the Ukrainian military told the Kyiv Post that several other soldiers had suffered similar injuries since 2014. “We are probably talking here about a retro-reflection detector,” Sean Tipper, the CTO of Sentinel Photonics, and former engineer at the UK’s Defence Science and Technology Laboratory (DSTL), told me on a call in August.

“There is a nefarious use for retroreflection devices, they can fire a high-energy pulse into the optic, which can severely damage the eyeball.

“Retroreflection is when light reflects off something at the focal plane of a scope or optic and travels back down that same path. It’s actually what happens when you shine a light at a cat’s eyes,” Sean explained. Essentially, retroreflection is the optical phenomenon of reflecting light directly back to its source, regardless of the angle at which the light hits the surface. This differs from a standard mirror, which only reflects light back at an equal and opposite angle to the incident light. “This can happen if laser light is shone into a sniper scope, so if you see your own laser reflected back to you then you know there is a scope or something there,” he continued.

Lasers are far from new on the battlefield, the Chieftain main battle tank carried one from 1969, and the US Air Force tested the laser-guided BOLT-117 bomb in Vietnam the year before. But retroreflection detection devices are different, in part because “they can be pulsed at much higher frequencies or they can be a continuous wave with no modulation,” Sean explained, before continuing, “there is a nefarious use for retroreflection devices, they can fire a high energy pulse into the optic, which can severely damage the eyeball. They [the manufacturers] state that they are not targeting the eye, they are targeting the optic, and the device would shatter the optic, but it would also damage the eye, causing a haemorrhagic lesion,” he continued. This was in reference to the Laws of Armed Conflict, which prohibit the use of lasers to target humans in this way. This series of events, starting with the unfortunate Ukrainian soldiers, set Sean and his co-founder down on the path that led to the founding of Sentinel Photonics. 

Sentinel Photonics, plough shares into beam directors? 

“Myself and my co-founder, Chris Burgess, worked at DSTL for five and 15 years respectively in the electro-optics protection measures team, designing measures to protect optics from lasers on the battlefield,” he recounted. The team successfully developed a new technology to detect lasers, but struggled to find an industry partner that could meet their own, lab-based build standards. “We knew there were systems out there like Russia’s PAPV, and similar hand-held systems from China that you can buy online, so we took the decision to spin Sentinel Photonics out of DSTL.” 

The PAPV is a portable laser countermeasure system developed by the Russian Nudelman Precision Engineering design bureau. Weighing 56 kg, the system is designed to detect and neutralise snipers and serve as an electro-optical countermeasure unit against military vehicles equipped with optical targeting systems, such as tanks and attack helicopters. The system uses a two-stage process. First, a low-power laser (2W) is used to scan for and locate enemy electro-optical systems. Once a system is detected, the PAPV then fires a more powerful laser pulse (1.5 Joules at 1.06 microns or 0.2 Joules at 0.53 microns) to disrupt and blind the targeted optical system. The effective operating range of the PAPV is between 300 and 1,500 metres.

“DSTL has a commercial arm called Ploughshare Innovations that supports tech commercially, they take patented technology and license it out to industry. We tried that with this technology but it didn’t work out,” Sean continued. As a result, Chris and Sean set Sentinel Photonics up in 2019, before officially spinning the organisation out of DSTL in October 2020. “So, the tech is approved by DSTL, but there is no special treatment and they have to compete commercially etc. but the MoD does own a stake in Sentinel through Ploughshare, and the IP is in the name of the Secretary of State for Defence,” he told me, providing a glimpse into the inner workings of the UK MoD, and its highly capable defence laboratory.

Now the team includes 20 staff members, with 11 in the technical team including Sean. “Our goal is to mitigate the threat on the battlefield, and we are very acutely aware of the lack of protection that exists,” Sean continued. And the list of threats is growing, already it includes laser range finders and designators, such as the system used by Russia’s Orlan-30, which is used to illuminate targets for strikes with the 152 mm Krasnopol laser guided artillery round. A sensor that detects these signals can provide valuable time for a vehicle or its crew to relocate before an engagement is completed. “Now there are high-energy laser weapons designed to counter drones and dazzle optics at tens or hundreds of kilometres, we can help forces detect and respond to them,” Sean said. 

The Sentinel Photonics solutions

The Sentinel Photonics solutions are divided into two categories, detect, and protect. Detection is provided by a number of systems designed for different applications from a personal system through to vehicle-mounted. “FROST is our protection solution for scopes and optics,” Sean explained. FROST is designed to be fitted to a rifle scope or optic using standard mounting threads and is available with three levels of protection. The first is “near infrared (NIR) protection, blocking common retroreflection system wavelengths, Level 2 extends protection beyond the NIR in order to also protect against longer wavelength threats. And Level 3 further provides direct laser exposure protection against additional threats,” the company’s website explains.

Sentinel Photonics has also developed  MICRO, a wearable laser detection system from Sentinel Photonics. Micro is approximately the size of a GoPro and has a very low false alarm rate, and can be plugged into a dismounted situational awareness system like the Android Team Awareness Kit (ATAK). Sean sees an opportunity for many laser warning receivers to be connected into a command and control system, providing wider awareness across a force. “So, if a helicopter or drone used a laser range finder, it could be detected by many people and give early warning of something incoming and then disperse the armour, for example. But you can only do that if you can detect the lasers,” he said. This draws on the company’s ability to provide intelligence on the type of laser that has been detected. 

“Micro can tell wavebands apart – SWIR or NIR – some designators work at certain frequencies that can be detected and propagated through a command and control system. Additionally, laser designators will fire a very specific code that can be picked up and dispersed across a unit. That could give an indication of what the system targeting you is,” he explained. This application could grow in importance for unit survivability. Russian units using Ka-52 attack helicopters have caused extensive damage to Ukrainian armoured formations during the 2023 counter-offensive, for example. The 9M120 Ataka missiles that they fire are laser beam riding, which would generate enough energy to trigger a warning on Sentinel’s MAX laser detection system. 

MAX is the product that Sean and Chris were developing at DSTL. “MAX provides warning of retro systems, laser beam riders etc. it is an all-round detector that can find everything that we are aware of on the battlefield. So, a sniper pair could take it with them, for instance, providing enhanced situational awareness,” Sean explained. FROST is designed to work in tandem with MAX, providing protection whilst MAX provides real time detection of threats, warning and intelligence gathering. The pairing allows for rapid development cycles for FROST, significantly shortening the development of new variants to counter new threats. Both FROST and MICRO are currently actively deployed, whilst “MAX will go through its full launch at DSEI, and it already has a few early adopters.” 

“We’ve done a lot of the hard work developing MAX, there were a few examples where I said, in my previous life, that industry would solve this problem, and I have now become that industry,” Sean recounted. “Our hope is that a low cost system will build this ecosystem [of laser protection], leading to more development of counter-measures. It is an enabler that means more technologies can be developed over time.” Sean concluded by saying. 

Calibre comment

Lasers are increasingly prominent on the battlefield and in the commercial space. In 2023, some 12,000 incidents of people shining laser pens at commercial aircraft were reported, according to the Laser Safety Certification organisation. Those incidents range from distracting to potentially very dangerous. “Pilots don’t know whether or not a laser is dangerous, and you can build goggles to protect against lasers, but not all wavelengths,” Sean explained. This means that flights, including those of rescue helicopters can be cancelled. Sentinel Photonics is looking at the application of its detectors in the civil and commercial space. “We can’t protect you from every wavelength, but we can tell you if it’s a threat,” Sean said. 

By Sam Cranny-Evans, published on August 28, 2025. Credit for the lead image is Sentinel Photonics, it shows a covert operator with a scope which could be targeted by retro-reflection devices.