Specification of Broadband Filters for JH and HK Spectroscopy -------------------------------------------------------- 1.3 - 2.3 um Broadband Filter -------------------------------------------------------- * Center wavelength 1.8 micron * Cut-on 1.3 micron * Cut-off 2.3 micron * Cut-on slope < 3% at 1.3 micron * Cut-off slope < 3% at 2.3 micron * Peak transmission > 80% average transmission (>90% goal) * Ripple specification Less than 5 % of average transmission * Out of band blocking E-4 0.8-1.3 micron E-5 2.3-2.6 micron * Physical dimension 80mm diameter 0.1mm * Clear aperture 70mm diameter (minimum) * Thickness 4-8mm * Substrate flatness < Lambda/4 * Substrate parallelism < 10 arcsec * Angle of Incidence ~6.2 degree * Operating temperature 120K * Operating range 0.85-2.5 micron * Quantity 2 * Free of pinhole defects. -------------------------------------------------------- 0.9 - 1.8 um Broadband Filter -------------------------------------------------------- * Cut-on 0.9 micron * Cut-on slope < 3% at 0.9 micron * Cut-off 1.78 micron * Out of band blocking E-4 0.7-0.9 micron E-5 1.9-2.6 micron * Slope < 3% * Peak transmission > 90% average * Quantity : 2 (# Detector operating range is 0.85-2.5 micron.)