OPTICAL DEVICE, LIGHT SOURCE DEVICE, OPTICAL HEAD DEVICE AND OPTICAL INFORMATION PROCESSING DEVICE

摘要

PROBLEM TO BE SOLVED: To realize a highly efficient and inexpensive light source device generating light of two wavelengths. SOLUTION: Light L1 polarized in the x axis direction of 650 nm wavelength is exited by a semiconductor laser 611. Light L2 polarized in the x axis direction of 780 nm wavelength is exited by a semiconductor laser 612. A wavelength plate 621 acts on light L1 as a (2m+1)λ/2 plate (m is an integer) and acts on light L2 as an nλ plate (n is an integer). Polarizing light in the x axis direction is diffracted by a polarization anisotropic hologram element 180 and polarizing light in the y axis direction is transmitted by the same. Consequently, an apparent light emitting point of diffracted light L2' coincides with a light emitting point of light L1.