An optical waveguide structure comprising a nonlinear optical waveguide, a central region, a first side region, and a second side region. The central region is located within the nonlinear optical waveguide, wherein the central region comprises a nonlinear optical material. The first side region is on a first side of the central region and the second side region is on a second side of the central region. The nonlinear optical material comprising the central region has a first nonlinear coefficient that is larger than a second nonlinear coefficient of a second material comprising the first side region and the second side region.

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.

A laser apparatus includes: a laser oscillator that includes a mirror and emits a laser beam; and an external resonator that includes a nonlinear optical crystal that functions as a phase conjugate mirror. The phase conjugate mirror reflects the laser beam and produces a phase conjugate wave that reaches the mirror of the laser oscillator, and the mirror of the laser oscillator and the phase conjugate mirror cause laser oscillation such that a wavelength and a phase of the laser beam oscillated by the laser oscillation are automatically fixed.

A laser processing system includes a laser source, an optical splitting unit, a frequency conversion unit and at least one optical mixer. The optical splitting unit is provided to divide light emitted by the laser source into a first light and a second light, and the first light and the second light have the same wavelength range. The frequency conversion unit is provided to convert the second light into a working light. The working light includes a frequency converted light, and the frequency converted light and the second light have different wavelength ranges. The optical mixer is provided to mix the first light with the frequency converted light.

A laser processing system includes a laser source, an optical splitting unit, a frequency conversion unit and at least one optical mixer. The optical splitting unit is provided to divide light emitted by the laser source into a first light and a second light, and the first light and the second light have the same wavelength range. The frequency conversion unit is provided to convert the second light into a working light. The working light includes a frequency converted light, and the frequency converted light and the second light have different wavelength ranges. The optical mixer is provided to mix the first light with the frequency converted light.

It remains a challenge to generate coherent radiation in the spectral range of 0.1-10 THz (“the THz gap”), a band for applications ranging from spectroscopy to security and high-speed wireless communications. Here, we disclose how to produce coherent radiation spanning the THz gap using efficient second-harmonic generation (SHG) in low-loss dielectric structures, starting from an electronic oscillator (EO) that generates coherent radiation at frequencies of about 100 GHz. The EO is coupled to cascaded, hybrid THz-band dielectric cavities that combine (1) extreme field concentration in high-quality-factor resonators with (2) nonlinear materials enhanced by phonon resonances. These cavities convert the input radiation into higher-frequency coherent radiation at conversion efficiencies of >10.sup.3%/W, making it possible to bridge the THz gap with 1 W of input power. This approach enables efficient, cascaded parametric frequency converters, representing a new generation of light sources extensible into the mid-IR spectrum and beyond.

It remains a challenge to generate coherent radiation in the spectral range of 0.1-10 THz (“the THz gap”), a band for applications ranging from spectroscopy to security and high-speed wireless communications. Here, we disclose how to produce coherent radiation spanning the THz gap using efficient second-harmonic generation (SHG) in low-loss dielectric structures, starting from an electronic oscillator (EO) that generates coherent radiation at frequencies of about 100 GHz. The EO is coupled to cascaded, hybrid THz-band dielectric cavities that combine (1) extreme field concentration in high-quality-factor resonators with (2) nonlinear materials enhanced by phonon resonances. These cavities convert the input radiation into higher-frequency coherent radiation at conversion efficiencies of >10.sup.3%/W, making it possible to bridge the THz gap with 1 W of input power. This approach enables efficient, cascaded parametric frequency converters, representing a new generation of light sources extensible into the mid-IR spectrum and beyond.

The disclosed laser system is configured with a laser source outputting light at a fundamental frequency. The output light is incident on a frequency converter operative to convert the fundamental frequency to a higher harmonic including at least one frequency converting stage. The frequency converter is based on a SrB.sub.4O.sub.7 (SBO) or PbB.sub.4O.sub.7 (PBO) nonlinear crystal configured with a plurality of domains. The domains have periodically alternating polarity of the crystal axis enabling a QPM use and formed with each with highly parallel walls which deviate from one another less than 1 micron over a 10 mm distance.

The disclosed laser system is configured with a laser source outputting light at a fundamental frequency. The output light is incident on a frequency converter operative to convert the fundamental frequency to a higher harmonic including at least one frequency converting stage. The frequency converter is based on a SrB.sub.4O.sub.7 (SBO) or PbB.sub.4O.sub.7 (PBO) nonlinear crystal configured with a plurality of domains. The domains have periodically alternating polarity of the crystal axis enabling a QPM use and formed with each with highly parallel walls which deviate from one another less than 1 micron over a 10 mm distance.