Fabri-Perot Spectral Filter that Preserves Image
Abstract
In some cases of active illumination of the target, high-resolution spectral selection may be used for discrimination between targets moving with different velocities and having different chemical compositions. Most monochromators and various spectrographs limit spatial and angular spread of input light, and thus distort the image. Volume diffraction grating at normal incidence may be used for spectral selection. However, spectral resolution delta v (1/cm) is about 1/L (i.e., limited by the longitudinal thickness L of the grating). The number of available image pixels is limited by the acceptance angle of the volume grating. Fabri-Perot interferometers (FPI) yield better spectral resolution. FPI with flat mirrors trades angle to the wavelength and thus distorts the image. Pierre Connes suggested in 1956 using Fabri-Perot interferometers with spherical mirrors, whose foci are coincident, for the spectral selection of broad areas and angles of input radiation. However, the image also is scrambled by confocal FPI (CFPI). The authors suggest a special arrangement of CFPI that yields high spectral selectivity and preserves the image. Post-paraxial approximation is developed for the modes. The number of resolvable image pixels is estimated based on corrections to the eigenfrequencies. (1 figure, 4 refs.)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 10, 2004
- Accession Number
- ADA428116
Entities
People
- Boris Zeldovich
- H. V. Sarkissian
Organizations
- University of Central Florida