Hamamatsu-Photonics K.k.

Other

Tadashi Kanabe

Toshiyuki Kawashima

Hirofumi Kan

Sadao Nakai

Osamu Matsumoto

The present invention relates to an optical mask at low cost and so on having a structure capable of reducing further a peak of beam intensity caused by diffraction. The optical mask is constructed by overlapping a first mask and a second mask. The first mask and second mask each are a serrated aperture mask. The schematic shapes of the respective apertures of the first mask and second mask are almost rectangular and identical to each other. The fringe defining the aperture of the first mask is machined in a serrated shape, and the fringe defining the aperture of the second mask also is machined in a serrated shape. In the optical mask, the first mask and second mask are overlapped so that the serrations of the fringes defining the respective apertures of the first mask and second mask are located alternately.

Optical mask and MOPA laser apparatus including the same

A solid-state laser apparatus which can improve its durability is provide. In the solid-state laser apparatus, a main pipefor circulating a coolant through a solid-state laser mediumis provided with a heat exchangerwhereby the laser mediumis prevented from raising its temperature. When the coolant becomes acidic or alkaline, a controllercontrols a flow regulating valve, so as to increase the flow rate of the coolant flowing into a bypass pipeprovided with a deionizing filter, whereby the acidity or alkalinity of the coolant can be weakened. This can prevent the coolant from deteriorating a predetermined part of the laser apparatus, and thus can improve the durability of the solid-state laser apparatus. Also, since the bypass pipeconnected in parallel to a part of the main pipeis provided with the deionizing filter, the flow rate of the coolant circulating through the main pipecan be restrained from decreasing, and the cooling efficiency of the laser mediumcan be prevented from lowering.

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Takarazuka, Japan

Tadashi Kanabe