LASER COMPONENTS sells dielectric optical filters drawn from PMMA in a newly developed thermoforming process. The filters, which have a maximum thickness of 500 µm, can be formed into any shape, opening up new possibilities: With hemispherical surfaces, the light always strikes the optics perpendicularly, regardless of its angle of incidence (AOI). This avoids the problem of blue shift that occurs with conventional optical interference filters as the AOI increases. In practice, it allows for bandpass filters with a narrower bandwidth and therefore a better signal-to-noise ratio.
The ultra-thin filters can be used at wavelengths between 370 nm and 1700 nm and have a thermal drift of about 0.1 nm/°C. All common filter types, from single- and multi-notch to long-pass, short-pass and band-pass filters, can be implemented with the new process.
»With the scalable, thin and flexible filters, many promising future applications open up,« says Björn Götze, who is responsible for the optical filter product area at LASER COMPONENTS. »I'm thinking, for example, of smartphones, wearables and endoscopic medical applications where classic dielectric filters are out of the question simply because of their thickness.«
