A novel atomic resonance filter with powerful solar background rejection is proposed. The filter wavelength matches the g Fraunhofer line at 422.7 nm. Atomic filtering occurs within the singlet manifold of neutral calcium. Superior sunlight discrimination arises mainly from two factors: overlay with an intense Fraunhofer line and signal levels devoid of fine and hyperfine structures. The new filter should exhibit high throughput and low noise.
© 1990 Optical Society of America
Original Manuscript: September 18, 1989
Manuscript Accepted: December 11, 1989
Published: February 15, 1990
Jerry A. Gelbwachs, "422.7-nm atomic filter with superior solar background rejection," Opt. Lett. 15, 236-238 (1990)