Abstract: A hologram recording medium includes a stack of at least a lower transparent substrate, a recording layer made of a photocurable organic material, and an upper transparent substrate, wherein a spacer for keeping a thickness of the recording layer is dispersed and disposed in the inside of the recording layer in a direction of a principal plane of the hologram recording medium.

Abstract: A holographic recording medium including a recording layer on a substrate, which records data information in a light interference pattern is provided. In the holographic recording medium, information on a thermal expansion characteristic of a recording material contained in the recording layer and/or information on temperature dependency of the refractive index of the recording material are recorded within the holographic recording medium in advance.

Abstract: An optical resonator includes a first substrate and a second substrate which face each other, the first substrate having a flat main surface on which a first reflective mirror is provided and the second substrate having a concave portion on which a second reflective mirror is provided and a flat portion which surrounds the concave portion. The main surface of the first substrate and the flat portion of the second substrate are bondable. In addition, a laser oscillator includes a solid-state laser medium and a substrate, the solid-state laser medium having a main surface on which a first reflective mirror is provided and the substrate having a concave portion on which a second mirror is provided and a flat portion which surrounds the concave portion. The first and the second reflective mirrors serve as a laser resonator.

Abstract: A multi-layered film made of sequentially stacked first dielectric layer, recording layer, record-assist layer, second dielectric layer and first reflection layer on a disc substrate having a concavo-convex structure at least on one surface thereof. An ultraviolet-setting resin layer is formed to cover the multi-layered film. The record-assist layer is controlled in thickness to satisfy the relation d/4<a<3d, or more preferably the relation d/2?a?2d, between the thickness d of the recording layer and the thickness a of the record-assist layer. The stacking order of the multi-layered film may be opposite. In this case, a light-transmitting sheet is provided to cover the multi-layered film via a bonding layer.

Abstract: A laser beam generation system comprises a solid state laser oscillator excited by an excitation beam, and a Q switch for pulsating laser oscillation by use of a saturable absorber, wherein the optical path length of a laser resonator is variable. The pulse of a laser beam generated from the laser beam generation system is detected, and variation of the optical path length of the laser resonator is controlled based on a characteristic of the detected pulse, to thereby stabilize the laser beam. The laser beam generation system may further comprise resonator length regulation element for varying the optical path length of the laser resonator, and detection element for detecting the pulse laser beam outputted, wherein the optical path length of the laser resonator is regulated by the resonator length regulation element based on a characteristic of the pulse detected by the detection element.

Abstract: An optical resonator includes a first substrate and a second substrate which face each other, the first substrate having a flat main surface on which a first reflective mirror is provided and the second substrate having a concave portion on which a second reflective mirror is provided and a flat portion which surrounds the concave portion. The main surface of the first substrate and the flat portion of the second substrate are bondable. In addition, a laser oscillator includes a solid-state laser medium and a substrate, the solid-state laser medium having a main surface on which a first reflective mirror is provided and the substrate having a concave portion on which a second mirror is provided and a flat portion which surrounds the concave portion. The first and the second reflective mirrors serve as a laser resonator.