Abstract

Among recent studies on holographic optical elements(HOEs) are those to develop compact substitutes for the beamsplitting prism and lens systems in the optical heads. The holographic heads^1-4 presented so far, however, have been based on the conventional servo-detection methods that required precise beam-positioning at the photodetectors. Thus HOEs, applied to both the astigmatic optics^2,3 and the double knife-edge method,^1,3,4 suffered some serious drawback due to the wavelength shift of the diode laser source, typically Δλ ≳ 5nm.^1,2

© 1989 Optical Society of America