Masers and microwave amplifiers that can function in the continuous-wave mode at room temperature are provided. The maser system can include a diamond gain medium having nitrogen-vacancy centers, and a resonator can be disposed around the gain medium. The resonator can be disposed in a cavity box, and radiation (e.g., visible light) can be provided to the gain medium to cause emission of microwave radiation.

A mid- to far-infrared solid state Raman laser system comprising a resonator cavity comprising: an input reflector adapted to be highly transmissive for light with a first wavelength in the range of about 3 to about 7.5 micrometers for admitting the first beam to the resonator cavity; and an output reflector adapted to be partially transmissive for light with a second wavelength greater than about 5.5 micrometers for resonating the second wavelength in the resonator and for outputting an output beam, the input reflector further being adapted to be highly reflective at the second wavelength for resonating the second wavelength in the resonator; and a solid state diamond Raman material located in the resonator cavity for Raman shifting the pump beam and generating the second wavelength.

Disclosed herein is a wafer processing method including a processed position measuring step of imaging an area including a beam plasma generated by applying a pulsed laser beam to a wafer, by using an imaging unit during the formation of a laser processed groove on the wafer, and next measuring the positional relation between the position of the beam plasma and a preset processing position. Accordingly, it is possible to check whether or not the laser processed groove is formed at a desired position, in real time during laser processing. If the position of the laser processed groove is deviated, the processed position can be immediately corrected.

Apparatus and method for the amplification of a laser beam by pumping a homogenous composite source beam through an amplification medium. A slab crystalline active medium is side-pumped via a pump module having a laser diode bar and an optical assembly. The optical assembly has a fast axis collimator and a lens in the fast axis and an array of slow axis collimators and the lens in the slow axis. The lenses are spaced so that the individual source beams from the emitters are: imaged upon a first facet of the amplification medium; have a beam waist at or near the first facet; are sized to fill the first facet; substantially overlap on the first facet; and are directed so that peripheral source beams undergo total internal reflection on entering the amplification medium. Embodiments of multiple laser diode bars and optical assemblies are described together with double side pumping arrangements.

An object is to provide an optical device capable of relaxing a manufacturing condition for an optical waveguide used in the optical device. An optical device 500 is provided with an optical waveguide 200 including a core and a cladding optically joined together, and a temperature controller 600 that controls temperature of the optical waveguide, wherein the optical waveguide includes the core and the cladding formed such that a normalized frequency specified for light propagating through the optical waveguide changes across a cutoff frequency of a guided mode determined from a structure of the optical waveguide in a temperature range in which a refractive index of the core is higher than a refractive index of the clad. The temperature controller controls the temperature of the optical waveguide over a temperature range across temperature at which the normalized frequency equals to the cutoff frequency.

The present application discloses a nonlinear optical crystal material, preparation method and application of the nonlinear optical crystal material. The nonlinear optical crystal material has an excellent infrared nonlinear optical performance, whose frequency-doubling intensity can reach 9.3 times of AgGaS.sub.2 with the same particle size, and it meets type-I phase matching; and its laser damage threshold can reach 7.5 times of AgGaS.sub.2 with the same particle size. The nonlinear optical crystal material has important application value in the frequency-converters which can be used for frequency doubling, sum frequency, difference frequency, optical parametric oscillation of laser in mid and far infrared waveband, and the like.

The present application is directed to a homogeneous laser light source having a temporally-variable seed source which includes at least one seed source configured to output at least one seed signal, the seed source configured to permit the user to selectively vary at least one temporal characteristic of the seed signal, at least one amplifier in communication with and configured to receive the seed signal and output at least one amplifier signal, at least one nonlinear optical generator is communication with the amplifier, the nonlinear optical generator configured to generate at least one homogeneous harmonic output signal in response to the amplifier signal, wherein the wavelength of the homogeneous harmonic output signal is different than the wavelength of the amplifier signal.

Disclosed herein is a wafer processing method including a processed position measuring step of imaging an area including a beam plasma generated by applying a pulsed laser beam to a wafer, by using an imaging unit during the formation of a laser processed groove on the wafer, and next measuring the positional relation between the position of the beam plasma and a preset processing position. Accordingly, it is possible to check whether or not the laser processed groove is formed at a desired position, in real time during laser processing. If the position of the laser processed groove is deviated, the processed position can be immediately corrected.

The present application is directed to a homogeneous laser light source and includes at least one modeless seed source configured to output at least one modeless seed signal, at least one amplifier in communication with and configured to receive the modeless seed signal from the seed source and output at least one modeless amplifier signal, and at least one nonlinear optical generator configured to receive the amplifier signal and generate at least one modeless harmonic output signal in response to the modeless amplifier signal, wherein the wavelength of the harmonic output signal is different than a wavelength of the modeless amplifier signal.

A method and system for generating femtosecond (fs) ultraviolet (UV) laser pulses enables stabile, robust, and optically efficient generation of third harmonic fs laser pulses using periodically-poled quasi-phase-matched crystals. The crystals have different numbers of periodically poled crystalline layers that enable a long conversion length without back-conversion and without a special phase-matching direction. The fs UV laser may have a high conversion efficiency and may be suitable for high power operation.