Sentinel Photonics delivers eye-safe covert optic detection directly to the warfighter

By Chris Burgess, CEO and Co-Founder, Sentinel Photonics

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The threat on the forward line

Hostile optics are among the least detectable and most consequential threats facing warfighters on the modern battlefield. Rifle scopes, spotting optics and covert surveillance lenses produce no thermal signature, no acoustic output, and no cue detectable by standard imaging equipment. By the time a conventional system identifies the source, the threat has already acquired its target.

The scale and variety of laser-based threats facing ground forces have grown significantly in recent years. Hostile laser activity across operational theatres spans rangefinders, target designators, dazzlers and directed-energy systems.

Adversaries are drawn to deploying these tools because they are fast, precise and difficult to detect before engagement.

The challenge of identifying covert optics before engagement is well documented in both research and on the front line, and can lead to irreparable damage.

For example, there have been numerous reports of incidents from Donbas in Ukraine, where service members have suffered often permanent eye damage while observing through binoculars or monoculars on sniper or surveillance missions. This is the result of retroreflection. Lasers are pulsed across an area, hit a lens and light is returned along the same path, revealing the presence of magnified optics. Nefarious use of retroreflection has seen adversaries then pulsing a high-power laser back into the optic, severely damaging eyeballs.

Retro-reflection-based detection is one of the most viable technical approaches currently available for locating magnified optics in the field. Until now, the laser safety constraints of every existing system have kept this capability out of the hands of dismounted defence and security teams.

A retroreflection detector locates optics and the person behind them without harming anyone, whereas a high-energy laser directed into optics can damage the optical path and the eye itself. International law specifically bans lasers designed to cause permanent blindness to unaided vision, but does not clearly ban all laser use against optical equipment, which is one reason the battlefield line between detection and blinding can be blurry.

Retro-reflection-based detection is one of the most viable technical approaches currently available for locating magnified optics in the field. Until now, the laser safety constraints of every existing system have kept this capability out of the hands of dismounted defence and security teams.

The consequences of that gap became starkly visible in July 2024. A post-incident analysis of the assassination attempt on then-former President Donald Trump1 noted that counter-sniper optics detection technology existed that could have been relevant to the scenario, while raising serious questions about whether it had been deployed or would have been operationally viable in an open, crowd-facing environment. For forces operating in those conditions, the absence of a safe, unrestricted detection capability is a direct liability.

The urgency for protection against retroreflection is broadly recognised across the sector. Lasers can turn anything into a target in seconds - seconds that the warfighter cannot spare.

Systems that don't make the cut

The majority of retro-reflective detection systems currently available use active laser illumination rated at Class 3B or above, meaning they are medium-power devices (5-500 mW) that are hazardous to the eye from direct viewing or specular reflections, but generally safe when viewing diffuse reflections.

At those power levels, the US Department of Defense laser safety handbook2 makes clear that exposure within the laser's hazard zone carries a serious risk of permanent damage to the retina, cornea and lens. That risk increases significantly when an observer is looking through optical aids such as binoculars or a rifle scope, which focus and amplify the returned beam directly into the eye.

In practice, this means these systems require a trained and qualified operator, a nominated Laser Safety Officer deployed alongside the equipment, and a defined Nominal Hazard Zone around the point of operation. Retro-reflective devices cannot lawfully be used in areas where third parties may be present, cannot be deployed at public events, and cannot operate in force-on-force training without extensive safety controls. At the forward line, where those controls are rarely achievable, these restrictions make existing systems operationally irrelevant.

Class 1 retro-reflective detection

In response, laser detection and prevention specialists, Sentinel Photonics, recently launched ECHO. This ruggedised, handheld retro-reflective detection system puts the ability to identify hostile and covert optical equipment directly into the hands of the dismounted warfighter.

ECHO is the first retro-reflective detection device in its class to operate at Class 1 by international laser safety classification. Class 1 is the highest safety classification for laser products and means it has been designed so that the maximum permissible exposure (MPE) for the human eye or skin is not exceeded, even if viewed directly or with optical aids for long periods.

And that means it is completely eye-safe and deployable in environments where no competing system can legally or safely operate, including open-crowd scenarios, public-facing protection operations, joint training exercises and forward-line positions where bystander presence cannot be controlled. This could include public-facing VIP protection operations, combined exercises with coalition and partner forces operating under different national laser safety frameworks, and FIBUA operations in urban terrain where civilian presence cannot be guaranteed.

ECHO is effective from 50 metres to three kilometres, even across day, low-light, and night conditions. Its Low Probability of Detection profile keeps the operator invisible to NVGs and NIR cameras throughout, meaning warfighters can scan for hostile optics without compromising their own position. It requires no specialist training and carries no laser safety restrictions.

Alongside active retro-reflective detection, ECHO passively identifies incoming lasers, providing dual-mode threat awareness from a single platform with no change of operating mode required.

For allied and partner forces, there is no additional qualification barrier. ECHO works within any operational context, without restriction. It puts retro-reflective detection capability directly into the hands of the individual warfighter, without the weight, complexity, or legal restrictions that have historically confined this technology to specialist teams.

ECHO represents a fundamental shift in how this class of capability is delivered to personnel at the front line.

Detection has to be organic to the soldier. A capability that requires a laser safety officer and a hazard zone is not a useful battlefield tool. ECHO enables the warfighter to detect hostile optics at range in any environment without permission. That is what forward line security demands.

For more information please visit:
https://sentinelphotonics.co.uk
mailto:[email protected]

References:
1 https://www.twz.com/news-features/experienced-snipers-break-down-the-trump-assassination-attempt
2 https://www.navsea.navy.mil/Portals/103/Documents/NSWC_Dahlgren/Laser/mil-hdbk_828B.pdf