摘要:
PROBLEM TO BE SOLVED: To provide a laser device producing a Gaussian distribution point-shaped beam having a remarkably strong light intensity, by wavelength conversion using a nonlinear optical crystal.SOLUTION: A laser device includes a nonlinear optical crystal NL having a period polarization inversion structure on which laser light emitted from a photonic crystal surface emission laser element LD impinges. The different refractive index region 6B of a photonic crystal layer is arranged at the grating point position of a square grating. When the planar shape of each different refractive index region 6B is substantially rectangular equilateral triangle, two sides constituting the right angle extend along the longitudinal and lateral grid lines of a square grating, and the orientation parallel with or perpendicular to the hypotenuse of the triangle matches the orientation of polarization in the period polarization inversion structure of the nonlinear optical crystal NL.
摘要:
PROBLEM TO BE SOLVED: To provide a terahertz-wave generating element including an electro-optic crystal, capable of modulating a generated terahertz wave at a relatively high speed.SOLUTION: The terahertz-wave generating element: includes a waveguide including an electro-optic crystal 4, that propagates light; an optical coupling member 7 which extracts a terahertz wave is generated from light propagating through the waveguide, to a space; and at least two electrodes 6a and 6b. The electrodes 6a and 6b has a function of changing a propagation state of the light propagating through the waveguide, by a first-order electro-optic effect in the electro-optic crystal 4 by applying an electric field to the waveguide. A crystal axis of the electro-optic crystal 4 of the waveguide is set such that the terahertz wave generated by a second-order nonlinear optical process and the light propagating through the waveguide are phase-matched.
摘要:
PROBLEM TO BE SOLVED: To provide a wavelength conversion device capable of keeping high efficiency of wavelength conversion for a longer time than that in the prior art. SOLUTION: When performing wavelength conversion of a second harmonic wave L2 in a fourth harmonic wave generating part 14, the incident position of the second harmonic wave L2 is relatively displaced in a direction including a projection direction component C1 of +C axis to the incident plane S1 in a BBO crystal 142 in the incident plane S1. Thereby, for example, when the BBO crystal 142 is deteriorated due to absorption of a fourth harmonic wave L4 in a deep ultraviolet area, the efficiency of wavelength conversion in the fourth harmonic wave generating part 14 is efficiently recovered. COPYRIGHT: (C)2010,JPO&INPIT