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Polymer Optics

Notch Filters

Enhancing Protection in Medicine and Defence

In a world where precision is critical to safety, G&H notch filters are making strides in both medical and military applications. Utilising a digitised rugate technique, our filters are transforming eye protection in ophthalmic surgeries and shielding military personnel and vehicles on the battlefield.

Laser eye surgery has revolutionised the field of ophthalmology, but with such powerful technology comes the need for equally powerful protection. This is where G&H’s notch filters play a crucial role. Used during ophthalmic laser eye surgery, our filters shield surgeons' eyes from harmful laser light, enabling them to perform delicate procedures safely and accurately. This form of protection is paramount to maintaining the eye health of those who work tirelessly to improve the sight of others.

At G&H, we don’t just manufacture notch filters; we advance them using a digitized rugate technique. This innovative approach allows us to adjust the width and depth of the notch at any wavelength, all while maintaining a high level of light transmission. The result is a filter tailored to specific needs, providing optimal protection without compromising visibility.

But the application of our notch filters extends beyond the operating room. On the battlefield, vision and safety go hand in hand. Our notch filters are incorporated into periscopes and other optical systems used by military personnel, acting as a crucial line of defense against potentially harmful light sources. Whether in combat or reconnaissance, these filters ensure that our servicemen and servicewomen can perform their duties safely, protecting their sight while they protect our security.

Moreover, G&H's notch filters form an essential part of Electro-Optical Protection Measures (EOPM) on military vehicles. These filters safeguard the electro-optical sensors from harmful radiation or laser attacks, ensuring their operability is not compromised and thus maintaining the vehicles' protective capabilities in high-risk situations.

One significant advantage of our notch filters is our ability to 'colour correct' the filter, making it as neutral as possible to the human eye. This means that while the filters block harmful wavelengths, they allow the rest of the visible spectrum to pass through unaffected, minimising colour distortion.

G&H's notch filters represent a fusion of science, innovation, and safety. They stand as proof of our commitment to protecting sight, whether in the surgical theatre or on the battlefield, ensuring clarity isn't compromised when it matters the most.


  • Transmission (IVPT Ill E) > 70%
  • OD > 4.5 @ 532nm AOI 0°-10°
  • Rejection bandwidth < 25nm as taken from the 10% transmission points
  • Excitation Purity < 20%
    • Colour Corrected
    • Transmission (IVPT Ill E) > 50%
    • Excitation Purity < 10%


  • Adhesion: ISO 9211-4-01-03 (severe)
  • Abrasion: ISO 9211-4-02-02
  • Humidity: ISO 9022-16-05-01
  • Contamination: ISO 9022-12 Severity 1 Evaluation as per criteria 0

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