A method of producing periodic polarization inversion structures requires the provision of first electrode piece part-arrays, each having electrode piece parts on a first main face of a ferroelectric crystal substrate. A voltage is applied on the first electrode piece part-arrays to form first periodic polarization inversion structures. Second electrode piece part-arrays are provided, each having electrode piece parts between the adjacent plural first periodic polarization inversion structures. A voltage is applied on the second electrode piece part-arrays to form second polarization inversion structures.

A method of producing periodic polarization inversion structures requires the provision of first electrode piece part-arrays, each having electrode piece parts on a first main face of a ferroelectric crystal substrate. A voltage is applied on the first electrode piece part-arrays to form first periodic polarization inversion structures. Second electrode piece part-arrays are provided, each having electrode piece parts between the adjacent plural first periodic polarization inversion structures. A voltage is applied on the second electrode piece part-arrays to form second polarization inversion structures.

Methods and systems are provided for separating polarized UV light. In one example, a method may include passing polarized source light through a group of at least four prisms to collimate and separate a second-harmonic generation (SHG) beam from a pump beam. The separated SHG beam may then be further passed through a spatial filter to reduce spatial distribution.

Methods and systems are provided for separating polarized UV light. In one example, a method may include passing polarized source light through a group of at least four prisms to collimate and separate a second-harmonic generation (SHG) beam from a pump beam. The separated SHG beam may then be further passed through a spatial filter to reduce spatial distribution.

Methods and apparatuses for manipulating and modulating of laser beams. The methods and apparatuses enable activating and deactivating of laser beams, while the laser systems maintain their operating power. Further, a hybrid pump module configured to be coupled to an optical fiber having a core and at least one clad, comprising: at least one focusing lens in optical with the optical fiber; plurality of diode modules, each configured to output a multi-mode beam in optical path with the clad; and at least one core associated module, in optical path with the core, configured to provide selected functions. Further, apparatus and methods configured for frequency doubling of optical radiation.

Methods and apparatuses for manipulating and modulating of laser beams. The methods and apparatuses enable activating and deactivating of laser beams, while the laser systems maintain their operating power. Further, a hybrid pump module configured to be coupled to an optical fiber having a core and at least one clad, comprising: at least one focusing lens in optical with the optical fiber; plurality of diode modules, each configured to output a multi-mode beam in optical path with the clad; and at least one core associated module, in optical path with the core, configured to provide selected functions. Further, apparatus and methods configured for frequency doubling of optical radiation.

According to one embodiment, a nitride crystal includes first, second, and third nitride crystal regions. The third nitride crystal region includes Al, and is provided between the first and second nitride crystal regions. A third oxygen concentration in the third nitride crystal region is greater than a first oxygen concentration in the first nitride crystal region and greater than a second oxygen concentration in the second nitride crystal region. A third carbon concentration in the third nitride crystal region is greater than a first carbon concentration in the first nitride crystal region and greater than a second carbon concentration in the second nitride crystal region. A <0001> direction of the first nitride crystal region is one of a first orientation from the second nitride crystal region toward the first nitride crystal region or a second orientation from the first nitride crystal region toward the second nitride crystal region.

According to one embodiment, a nitride crystal includes first, second, and third nitride crystal regions. The third nitride crystal region includes Al, and is provided between the first and second nitride crystal regions. A third oxygen concentration in the third nitride crystal region is greater than a first oxygen concentration in the first nitride crystal region and greater than a second oxygen concentration in the second nitride crystal region. A third carbon concentration in the third nitride crystal region is greater than a first carbon concentration in the first nitride crystal region and greater than a second carbon concentration in the second nitride crystal region. A <0001> direction of the first nitride crystal region is one of a first orientation from the second nitride crystal region toward the first nitride crystal region or a second orientation from the first nitride crystal region toward the second nitride crystal region.

An all-optical optical parametric oscillator includes a laser module, a temperature control module, a plurality of filters and a beam splitter arranged in sequence. A bulk material or waveguide material is arranged in the temperature control module. Both ends of the bulk material are provided with a first OPO cavity mirror M.sub.1′ and a second OPO cavity mirror M.sub.2′. Each of the first OPO cavity mirror M.sub.1′ and the second OPO cavity mirror M.sub.2′ is coated with a high-reflectivity film with respect to an OPO signal light and an OPO idler light, and coated with a high-transmittance film with respect to an OPO pump light, a poling fundamental frequency light and a poling frequency doubled light. The temperature of the material is changed by changing the temperature of the temperature control module to realize temperature tuning of wavelength λ.sub.s of the OPO signal light and wavelength λ.sub.i of the OPO idler light.

An all-optical optical parametric oscillator includes a laser module, a temperature control module, a plurality of filters and a beam splitter arranged in sequence. A bulk material or waveguide material is arranged in the temperature control module. Both ends of the bulk material are provided with a first OPO cavity mirror M.sub.1′ and a second OPO cavity mirror M.sub.2′. Each of the first OPO cavity mirror M.sub.1′ and the second OPO cavity mirror M.sub.2′ is coated with a high-reflectivity film with respect to an OPO signal light and an OPO idler light, and coated with a high-transmittance film with respect to an OPO pump light, a poling fundamental frequency light and a poling frequency doubled light. The temperature of the material is changed by changing the temperature of the temperature control module to realize temperature tuning of wavelength λ.sub.s of the OPO signal light and wavelength λ.sub.i of the OPO idler light.