Test-beds for evaluation of laser protection filters and components

Since the early nineties FOI has developed and evaluated laser protection devices. The earlier developed test-beds have now been further enhanced and standardised to secure the optical measurements and to simplify the evaluation procedure. Three different test-beds have been designed and built; a test-bed for studying agile and static protection devices and two test beds for studying self- activated protection devices - one for large aperture lenses and one for smaller aperture lenses. The test-bed for studying agile and static devices meets the requirements of the American military standard, which is compatible with the European standard. Switching time for the agile devices, i.e. the time between open and closed state, is measured according to VESA (Video Electronics Standards Association) standard procedure but adapted to the conditions for laser protection. Optical limiting (self-activated) protection devices are analysed in accordance with a NATOstandard. With these test beds it is possible to analyse/evaluate all the different types of laser protection devices under development and static protection devices that are commercially available. Above all the following parameters can be quantified:  Attenuation; ability of the protection devices to reduce the transmitted laser light.  Tunability (agile protection devices); control of the spectral transmittance.  Broadband optical limiting performance (self-activated protection devices).  Switching time (agile protection devices); time from laser light detection to attain a protective state (closed).  Spectral transmission including photopic transmission.  Angular-dependency; the degree of transmittance with respect to the angle of incidence for the light in the protection devices.  Damage threshold; laser energy at which irreversible damage occurs in the device. Apart from being used to test the protection devices developed, the test-beds can also be used to assist other departments within the Swedish Armed Forces or civilian stakeholders with measurements/evaluations of laser protection devices. Control electronics and software developed by FOI can be used in field-tests and can be further developed, i.e. customised for a particular protection device for a faster and more secure use in the field.