Shorter wavelength light generating apparatus in which coherent light is converted into shorter wavelength light

A shorter wavelength light generating apparatus for generating shorter wavelength light of which a wavelength is changeable, comprising:

• a semiconductor laser for initially radiating various modes of coherent light including a required mode of coherent light, a wavelength of the required mode of coherent light differing from those of the other various modes of coherent light;
• a reflection type of diffraction grating for diffracting the various modes of coherent light radiated from the semiconductor laser at various angles of diffraction and reflecting the various modes of coherent light diffracted;
• a rotating base for adjustably inclining the reflection type of diffraction grating to selectively feed back the required mode of coherent light to the semiconductor laser, the required mode of coherent light fed back to the semiconductor laser inducing the semiconductor laser to dominantly radiate the required mode of coherent light;
• and
• wavelength converting device composed of a plurality of regions which each has a group of alternate rows of reverse and non-reverse polarization layers arranged at regular intervals, the regular intervals of a group of alternate rows differing from those of the other groups of alternate rows, and a part of the required mode of coherent light dominantly radiated from the semiconductor laser being converted into the shorter wavelength light in one of the groups of alternate rows.

A shorter wavelength light generating apparatus, comprising:

• coherent light radiating means for initially radiating a required mode of coherent light and other various modes of coherent light, a wavelength of the required mode of coherent light differing from those of the other various modes of coherent light;
• light diffracting means composed of a reflection type of diffraction grating for diffracting the required mode of coherent light radiated from the coherent light radiating means at a feedback angle of diffraction to feed back the required mode of coherent light diffracted to the coherent light radiating means and diffracting the other various modes of coherent light radiated from the coherent light radiating means at an abandoned angle of diffraction to abandon the other various modes of coherent light diffracted, a plurality of circular gratings being concentrically formed in the reflection type of diffraction grating, and the required mode of coherent light fed back to the coherent light radiating means inducing the coherent light radiating means to dominantly radiate the required mode of coherent light;
• and
• wavelength converting means for converting a part of the required mode of coherent light dominantly radiated from the coherent light radiating means in cooperation with the light diffracting means into shorter wavelength light of which a wavelength is shorter than that of the required mode of coherent light, the wavelength converting means being composed of a bulk element type of wavelength converting device in which alternate rows of reverse and non-reverse polarization layers are arranged at regular intervals, the required mode of coherent light passing through the bulk element type of wavelength converting device while spreading in conical shape being diffracted by the circular gratings of the reflection type of diffraction grating to the coherent light radiating means, and the shorter wavelength light converted in the bulk element type of wavelength converting device while spreading in conical shape being diffracted by the circular gratings at an output angle of diffraction to output the shorter wavelength light.

A shorter wavelength light generating apparatus, comprising:

• coherent light radiating means for initially radiating a required mode of coherent light and other various modes of coherent light, a wavelength of the required mode of coherent light differing from those of the other various modes of coherent light;
• light diffracting means composed of a reflection type of diffraction grating for diffracting the required mode of coherent light radiated from the coherent light radiating means at a feedback angle of diffraction to feed back the required mode of coherent light diffracted to the coherent light radiating means and diffracting the other various modes of coherent light radiated from the coherent light radiating means at an abandoned angle of diffraction to abandon the other various modes of coherent light diffracted, a plurality of linear gratings being formed in parallel in the reflection type of diffraction grating, and the required mode of coherent light fed back to the coherent light radiating means inducing the coherent light radiating means to dominantly radiate the required mode of coherent light;
• wavelength converting means for converting a part of the required mode of coherent light dominantly radiated from the coherent light radiating means in cooperation with the light diffracting means into shorter wavelength light of which a wavelength is shorter than that of the required mode of coherent light, the wavelength converting means being composed of a bulk element type of wavelength converting device in which alternate rows of reverse and non-reverse polarization layers are arranged at regular intervals, the required mode of coherent light being diffracted by the linear gratings to the coherent light radiating means, and the shorter wavelength light converted in the bulk element type of wavelength converting device being diffracted by the linear gratings at an output angle of diffraction to output the shorter wavelength light;
• and
• collimating means for collimating the required mode of coherent light dominantly radiated from the coherent light radiating means, the required mode of coherent light collimated by the collimating means being radiated to the wavelength converting means.

A shorter wavelength light generating apparatus, comprising:

• coherent light radiating means for initially radiating a required mode of coherent light and other various modes of coherent light, a wavelength of the required mode of coherent light differing from those of the other various modes of coherent light;
• light diffracting means composed of a refection type of diffraction grating for diffracting the required mode of coherent light radiated from the coherent light radiating means at a feedback angle of diffraction to feed back the required mode of coherent light diffracted to the coherent light radiating means and diffracting the other various modes of coherent light radiated from the coherent light radiating means at an abandoned angle of diffraction to abandon the other various modes of coherent light diffracted, a plurality of linear gratings being formed in parallel in the reflection type of diffraction grating, and the required mode of coherent light fed back to the coherent light radiating means inducing the coherent light radiating means to dominantly radiate the required mode of coherent light;
• wavelength converting means for converting a part of the required mode of coherent light dominantly radiated from the coherent light radiating means in cooperation with the light diffracting means into shorter wavelength light of which a wavelength is shorter than that of the required mode of coherent light, the wavelength converting means being composed of a bulk element type of wavelength converting device in which alternate rows of reverse and non-reverse polarization layers are arranged at regular intervals, the required mode of coherent light being diffracted by the linear gratings of the reflection type of diffraction grating to the coherent light radiating means, and the shorter wavelength light converted in the bulk element type of wavelength converting device being diffracted by the linear gratings at an output angle of diffraction to output the shorter wavelength light;
• and
• collimating means for collimating the required mode of coherent light and the shorter wavelength light radiated from the wavelength converting means, the required mode of coherent light and the shorter wavelength light collimated by the collimating means being radiated to the light diffracting means.

A shorter wavelength light generating apparatus, comprising:

• coherent light radiating means for initially radiating a required mode of coherent light and other various modes of coherent light, a wavelength of the required mode of coherent light differing from those of the other various modes of coherent light;
• light diffracting means for diffracting the required mode of coherent light radiated from the coherent light radiating means at a feedback angle of diffraction to feed back the required mode of coherent light diffracted to the coherent light radiating means and diffracting the other various modes of coherent light radiated from the coherent light radiating means at an abandoned angle of diffraction to abandon the other various modes of coherent light diffracted, the required mode of coherent light fed back to the coherent light radiating means inducing the coherent light radiating means to dominantly radiate the required mode of coherent light;
• and
• wavelength converting means for converting a part of the required mode of coherent light dominantly radiated from the coherent light radiating means in cooperation with the light diffracting means into shorter wavelength light of which a wavelength is shorter than that of the required mode of coherent light, the wavelength converting means being composed of an optical waveguide type of wavelength converting device in which alternate rows of reverse and non-reverse polarization layers are arranged at regular intervals in an optical waveguide, material of the optical waveguide type of wavelength converting device being selected from the group consisting of LiTaO.sub.3, LiNbO.sub.3, KTiOPO.sub.4 and KNbO.sub.3, and the shorter wavelength light being output from the wavelength converting means.

A shorter wavelength light generating apparatus comprising:

• coherent light radiating means for initially radiating a required mode of coherent light and other various modes of coherent light, a wavelength of the required mode of coherent light differing from those of the other various modes of coherent light;
• light diffracting means for diffracting the required mode of coherent light radiated from the coherent light radiating means at a feedback angle of diffraction to feed back the required mode of coherent light diffracted to the coherent light radiating means and diffracting the other various modes of coherent light radiated from the coherent light radiating means at an abandoned angle of diffraction to abandon the other various modes of coherent light diffracted, the required mode of coherent light fed back to the coherent light radiating means inducing the coherent light radiating means to dominantly radiate the required mode of coherent light;
• and
• wavelength converting means for converting a part of the required mode of coherent light dominantly radiated from the coherent light radiating means in cooperation with the light diffracting means into shorter wavelength light of which a wavelength is shorter than that of the required mode of coherent light, the wavelength converting means being composed of a bulk element type of wavelength converting device in which alternate rows of reverse and non-reverse polarization layers are arranged at regular intervals, material of the bulk element type of wavelength converting device being selected from the group consisting of LiTaO.sub.3, LiNbO.sub.3, KTiOPO.sub.4 and KNbO.sub.3, and the shorter wavelength light being output from the wavelength converting means.