Abstract: An optical filter includes a glass substrate having a first main surface, a second main surface opposite the first main surface, and an end surface connecting the first and second main surfaces, the glass substrate being a phosphate glass containing an absorbent, and a first antireflection layer disposed directly or indirectly on the first main surface of the glass substrate, wherein the first main surface of the glass substrate is coated with a first inorganic film, and a second inorganic film is provided directly or indirectly on the second main surface of the glass substrate, with the end surface being coated with a third inorganic film, and wherein the first inorganic film is a film that is closest to the glass substrate among films constituting the first antireflection layer, or a film that is different from a film composed of a plurality of films constituting the first antireflection layer.

Abstract: The present invention relates to an optical filter including an absorption layer containing a near-infrared absorbing dye and a resin, in which the near-infrared absorbing dye contains a squarylium dye having a maximum absorption wavelength in 650 to 780 nm and a thermal decomposition temperature of 265° C. or higher and satisfying IR20?IR80<65 nm, and the resin has a glass transition temperature of 390° C. or higher.

Abstract: A liquid crystal optical modulation element to modulate a laser beam having a wavelength of at most 500 nm, which contains a layer of a liquid crystal composition sandwiched between a pair of transparent substrates facing each other, wherein each transparent substrate has an electrode and an alignment film having a polyimide on the surface which faces the other transparent substrate, the alignment film and the liquid crystal composition are in contact with each other, and the liquid crystal composition contains at least one antioxidant.

Abstract: To provide a liquid crystal optical modulation element capable of stably modulating a laser beam having a wavelength of at most 500 nm for a long period of time. A liquid crystal optical modulation element to modulate a laser beam having a wavelength of at most 500 nm, which comprises a layer of a liquid crystal composition sandwiched between a pair of transparent substrates facing each other, characterized in that each of the pair of transparent substrates has an electrode and an alignment film comprising a polyimide on the surface which faces the other transparent substrate, the alignment film and the liquid crystal composition are in contact with each other, and the liquid crystal composition contains an antioxidant.