Cyber Laser Inc.

Japan Science and Technology Agency

Taisuke Miura

Hitoshi Sekita

Kazuya Takasago

Yusuke Tamaki

Hideo Hosono

Masahiro Hirano

Kenichi Kawamura

Hayato Kamioka

Disclosed is a method of producing a hologram through a two-beam laser interfering exposure process, which comprises emitting a coherent laser light with a pulse width (&#x3c4;) ranging from greater than 900 femtoseconds to 100 picoseconds and a laser power of 10 &#x3bc;J/pulse or more using a solid-state laser as a light source, dividing the pulses light from the laser into two beams, controlling the two beams temporally and spatially in such a manner that the two beam are converged on a surface of or inside a workpiece for recording a hologram while matching the respective converged spots of the two beams with one another temporally and spatially to create the interference therebetween so as to record a surface-relief hologram on the surface of the workpiece or an embedded hologram inside the workpiece in an irreversible manner. The present invention can solve a problem with a conventional process of recording a hologram in a non-photosensitive material in an irreversible manner using interfering femtosecond laser pulses, specifically, distortion in the waveforms of pulsed laser beams and resulting instability in recording of an embedded hologram due to a non-linear optical interaction between the femtosecond laser pulses and air/the material.

Method for producing hologram by pico-second laser

The present invention offers a laser oscillator device having sufficient cooling ability to maintain a lasing medium which generates high-density thermal energy at a temperature appropriate for use, while being capable of being made compact. The laser oscillator device comprises an excitation beam source for generating an excitation beam, a laser medium for receiving the excitation beam and performing optical amplification, a laser oscillator device for causing resonance of light emitted by the laser medium for laser oscillation, and a cooling system for cooling said laser medium, wherein the cooling system uses a gas as the heat-carrying medium.

Helium-cooled laser device

The present invention has the object of offering a laser resonator capable of maintaining high amplification efficiency even if the thermal lensing effect occurring in the laser medium varies during operation or over repeated operation and suspension of the laser device. The laser resonator comprises at least a pair of reflection portions (planar reflective mirrors) provided such as to allow a laser beam to oscillate therebetween; a laser medium provided on the optical path of the laser between the pair of reflection portions; an excitation portion (excitation laser device) for exciting the laser medium; an optical system (convex lens) provided on the optical path of the laser beam between the laser medium and the pair of reflection portions for changing the state of the laser in the laser medium; and a movement portion for moving the optical system along the optical axis of the laser.

Laser resonator and adjustment method

The invention offers a regenerative optical amplifier enabling voltage to be easily applied to polarizing elements such as Pockels cells, without the need for complicated drive circuitry. An input beam of S-polarized light is reflected by a polarizerand advances to a Pockels cell. In the time it takes for the input beam, having once passed through the Pockels cell, to be reflected by a reflective mirrorand return to the Pockels cell, a voltage Vcausing a 90-degree rotation in the polarization of transmitted light is applied to the Pockels cell, and this applied voltage Vis maintained. The input beam is converted by the Pockels cellinto a P-polarized light pulse which is transmitted by the polarizer. Subsequently, the light pulse is converted from P-polarized light to S-polarized light and back to P-polarized light with each roundtrip of the Pockels cell, while passing each time between the reflective mirror, laser crystaland reflective mirror, so as to be amplified in the resonator formed thereby. The amplified light pulse is extracted by applying a voltage Vcausing a 90-degree rotation of the polarization of the transmitted light to the Pockels cellto convert the light pulse to S-polarized light which is then reflected out of the resonator by the polarizer

Growing community of inventors

Kanagawa, Japan

Taisuke Miura