OPTICAL HEAD AND SECOND HIGHER HARMONIC LIGHT SOURCE

摘要

PURPOSE:To constitute the optical head which has a short optical path by diffusing a light beam as a 2nd higher harmonic generated by the 2nd higher harmonic light source as to the optical disk which uses the 2nd higher harmonic light source. CONSTITUTION:When a light beam 2 is made incident on the 2nd higher harmonic generating means 4, a solid laser element 5 is excited to generate a light beam 8. When the light beam 8 is made incident on a nonlinear optical element 6, the light beam 9 as the 2nd higher harmonic is generated with the incident light beam as a fundamental wave. The light beam 8 is amplified by a resonator consisting of an end surface 7a of a resonance element and an end surface 5a of the solid laser element 5 to increase the quantity of the light beam 9. The light beam 9 is diffused by the concave projection surface 7b of the resonance element 7 when passing through the resonance element 7 to become a light beam 10. This light beam 10 is converged by an objective 12 to constitute the practical optical head which has the short optical path.