Case Study: MID Infra-Red Broadband Attenuator

Customer Problem: The customer required a broadband attenuator to operate in the mid infra-red from 2.5 to 5 µm. The system had several lasers operating across the band, all of which needed attenuating before being incident on the system detector. The surface quality was particularly demanding for an IR application.

Our Solution: This represents quite a challenge to ensure the response is level over such a wide band, we were able to design such a coating and a wide band AR coating to go on the other surface. The flexibility in our on-site plant, meant we were able to make this in one off our ‘side sputter’ configured machines, which we know gives excellent surface quality. The customer also expected the filter to pass certain LIDT thresholds for a range of lasers, this was incorporated into the original design and samples were tested at a well-known industry test house off-site to ensure compliance.

Outcome: This particular part is now a routine production filter for Vortex and is supplied to the end user on a monthly call off basis. The transmission performance is shown above.