Multi BBAR Coatings

Multi Broadband AR coatings operate over two or more spectral bands. In most cases it involves visible plus one or more bands in IR. Spectral performance of a typical two-band AR coating designed for CaF₂ substrate is shown in plot below. Designs with similar performance

Rav <1% @ 500-900 nm & 3.3–5.5µ @ 0°-15°
SUBSTRATE IS CaF₂

are available for any other IR material transparent within 500 nm and 5.5 µ range, e.g. ZnS, Al2O3, MgF2, and BaF2.

Rav <0.5% @ 600-700 nm & 1450-1650 nm
@ 0°-15° SUBSTRATE IS BK7

The previous plot shows spectral response of the 2-band AR coating designed to operate over spectral bands covering 600-700 nm and 1450-1650 nm. This coating is commonly used in applications where a red lasers or laser diode is used for alignment of telecom S-, C-, and L- band laser lines. Plot below shows four band AR coating covering range from 2.1-2.9µ, 3.3-4.0µ, 6.0–6.7µ, and 7.2-8.1µ

Rav <1% @ 2.0-4.0µ& 6.0–8.0 µ @ 0°-5°
SUBSTRATE IS ZnSe

Plot below shows dual band AR operating over most of the visible and 780-1000 nm NIR band with very high efficiency.

Rav <0.25% @ 450-600 nm & 770-1000 nm
@ 0°-20° HIGH INDEX SUBSTRATE