A dual-band optics design for disjoint spectral bands and for a cooled FPA sensor, sensitive to both bands, is presented. The use of special optical splitting mechanisms enables matching the optical paths of both bands to the same sensor. Reasonable optical performance and good registration were achieved for dual bands such as 8 to 12 μm together with 3.6 to 4.2 μm, and for the 3.6 to 4.2 μm band with various monochromatic laser bands in the 1.06 to 1.8 μm spectral range. Regular IR materials were used with aspheric and diffractive surfaces. Both single-objective designs and zoomed-objective designs are presented.
Conventional optical elements have been replaced by diffractive ones in order to improve the performance of IR optical systems.
Two examples are represented here.The first optical system is a MWIR scanning objective composed of air spaced doublet of CaF2 and As2S3 lenses. The combination of these materials gives an achromatic and passively athermalised optical system. It has been required to replace the As2S3 by an environmental approved material while retaining the achromatic and passively athermalised qualities.
A new objective composed of ZnSe and Germanium lenses, where one of the Germanium surfaces is a diffractive one, has been designed to be also achromatic and passively athermalised. The two designs share similar optical performance. The second optical system is an objective for InSb Focal Plane Array Sensor at the MWIR spectral range. The optics includes ZnS, CaF2, Silicon and Germanium lenses. The requirement is to image a 1.06 micron laser spot on the InSb sensor. A new design composed of a front ZnS lens and 5 ZnSe lenses enables the transmittance of both the MWIR and the 1.06 micron spectral bands. Two diffractive surfaces are added to correct the chromatic aberration at the MWIR. A third diffractive surface enables focusing the 1.06 micron spot at the same plane as the MWIR image.
An optical design study for a next generation infrared space telescope has been performed. The concept is that of a passively cooled telescope of minimum aperture 2.5 meter with an F/1.2 primary and wavelength coverage from (lambda) equals 2 to at least 40 micrometers , and possibly to 100 micrometers . Compactness, low thermal emission from the optics and structure, diffraction limited imaging at (lambda) equals 2 micrometers , and sensitivity to misalignment aberrations and manufacturing errors were the main considerations for this study. Ray tracing results are presented showing the characteristics of the various designs considered. A preliminary investigation of stray light properties is also given. Special emphasis has been placed on the testing of such a fast primary, and optical systems using a lateral shearing interferometer are described for testing both the primary and the primary/secondary combination.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.