Abstract: An optical attenuator has a sampling prism, a biconcave lens and an absorption member. A branch member splits a laser beam. An expansion member expands the shape of the split laser beam. The absorption member absorbs the energy of the expanded laser beam. A light receiving part of the absorption member receives the expanded laser beam. A first distribution part of the absorption member adjacent to the light receiving part, introduces or leads out a medium (cooling water) from a first opening and distributes the medium, which absorbs heat generated in the light receiving part by the laser beam. A second distribution part of the absorption member leads out or introduces cooling water from a second opening, and distributes the cooling water, which moves through a communicating part that communicates with the first distribution part.

Abstract: An optical attenuator has a sampling prism, a biconcave lens and an absorption member. A branch member splits a laser beam. An expansion member expands the shape of the split laser beam. The absorption member absorbs the energy of the expanded laser beam. A light receiving part of the absorption member receives the expanded laser beam. A first distribution part of the absorption member adjacent to the light receiving part, introduces or leads out a medium (cooling water) from a first opening and distributes the medium, which absorbs heat generated in the light receiving part by the laser beam. A second distribution part of the absorption member leads out or introduces cooling water from a second opening, and distributes the cooling water, which moves through a communicating part that communicates with the first distribution part.