Reflecting mirror and optical pickup

An optical pickup, comprising:

• a light source for emitting at least a light beam at wavelength of 405 nm, a light beam at wavelength 640 nm, and a light beam at wavelength 780 nm;
• a polarized beam splitter;
• a λ/4 wave plate and photodetector;
• and
• a reflecting mirror, in which a light path is formed to and from said light source, said polarized beam splitter, said λ/4 wave plate and photodetector and said reflecting mirror;
• said reflecting mirror comprising:
• a first reflective multi-layer coating formed on a substrate plate by alternately depositing a low refractivity layer and a first high refractivity layer absorptive of a wavelength of 405 nm having a refractivity higher than said low refractivity layer of the first reflective multi-layer coating;
• and
• a second reflective multi-layer coating formed at a light incident side of said first reflective multi-layer coating, by alternately depositing a low refractivity layer and a non-absorptive second high refractivity layer having a refractivity higher than said low refractivity layer of the second reflective multi-layer coating but lower than said first high refractivity layer in said first reflective multi-layer coating;
• wherein an incident light beam at a wavelength of 405 nm is reflected off by said second reflective multi-layer coating while incident light beams at wavelengths of 640 nm and 780 nm are reflected off by cooperative actions of said first and second reflective multi-layer coatings;
• and
• wherein said second reflective multi-layer coating reflects off part of incident light beams at wavelengths of 640 nm and 780 nm.