Beck Optronic Solutions has designed a range of fixed focal length and zoom lenses for SWIR (0.7-1.7µm) wavelengths for use with the latest Indium Gallium Arsenide (InGaAs) detectors.
Light in the short-wave infrared
(SWIR) waveband is invisible to the human eye and requires
specialised detectors such as Indium Gallium Arsenide (InGaAs).
However, it interacts with objects in a similar fashion to visible
light in that it is reflected, rather than emitted as is the case
in mid-wave infrared (MWIR) (3-5μm) and long-wave infrared (LWIR)
(8-12μm) wavebands. Because of this reflected nature SWIR imagery
shows shadows and contrast and is comparable to visible imagery in
terms of detail and resolution, although SWIR images are not in
colour.
There are many applications that
are possible using SWIR that would be difficult or impossible to
perform using visible light. For example fog and water vapour are
transparent to SWIR and colours that might be indistinguishable in
the visible may be easily differentiated using SWIR.
For low light conditions, SWIR
detectors allow the images to be transmitted electronically -
something that is difficult using the traditional image
intensification technology. Natural night sky radiance is
primarily in the SWIR waveband, and provides significantly more
illumination than starlight in the visible spectrum providing
advantages in certain low light conditions. Using lasers or
LEDs operating at the 1550nm wavelength, SWIR offers the
opportunity to covertly illuminate a scene that can only be
observed using a SWIR camera.
Using or adapting a lens in SWIR
that was designed for the visible waveband will give lower
performance in terms of resolution and optical aberrations and
offer reduced light transmission. All Davin Optronic's SWIR
products are specifically designed and optimised from first
principles to deliver the best SWIR performance using appropriate
optical materials and coatings. Finally the performance of every
lens is validated through SWIR waveband MTF testing.
