Abstract: A frequency double or mixing laser includes a laser pump, a rear optical element, a Brewster window, a laser generator medium, an output coupler and a nonlinear crystal located inside the resonator cavity. The nonlinear crystal may be located inside the resonator cavity before the output coupler. The laser may further include at least one optical element that controls the phase or/and the amplitude of the fundamental laser beam to a high-order.

Abstract: Laser apparatus includes an output coupler, a gain medium for generating laser light, a rear optical element, and an input coupler. The input coupler is arranged to direct a pump beam to the gain medium and to define an optical path between the output coupler and the rear optical element. The rear optical element is a spatial light modulator arranged to act as an intra-cavity digital holographic mirror which can be digitally addressed. The spatial light modulator displays selectively a gray-scale image of a hologram thereby to phase-modulate laser light in the cavity, thus making it possible to generate an output laser beam having a desired characteristic. The apparatus includes a computer arranged to generate at least one hologram corresponding to a desired output beam characteristic, and a driver circuit responsive to an output from the computer to generate a corresponding gray-scale image of the hologram on the spatial light modulator.

Abstract: A method and apparatus for performing a modal decomposition of a laser beam are disclosed. The method includes the steps of performing a measurement to determine the second moment beam size (w) and beam propagation factor (M2) of the laser beam, and inferring the scale factor (wO) of the optimal basis set of the laser beam from the second moment beam size and the beam propagation factor, from the relationship: wO=w/M2. An optimal decomposition is performing using the scale factor wO to obtain an optimal mode set of adapted size. The apparatus includes a spatial light modulator arranged for complex amplitude modulation of an incident laser beam, and imaging means arranged to direct the incident laser beam onto the spatial light modulator. Fourier transforming lens is arranged to receive a laser beam reflected from the spatial light modulator.

Abstract: Laser apparatus includes an output coupler, a gain medium for generating laser light, a rear optical element, and an input coupler. The input coupler is arranged to direct a pump beam to the gain medium and to define an optical path between the output coupler and the rear optical element. The rear optical element is a spatial light modulator arranged to act as an intra-cavity digital holographic mirror which can be digitally addressed. The spatial light modulator displays selectively a gray-scale image of a hologram thereby to phase-modulate laser light in the cavity, thus making it possible to generate an output laser beam having a desired characteristic. The apparatus includes a computer arranged to generate at least one hologram corresponding to a desired output beam characteristic, and a driver circuit responsive to an output from the computer to generate a corresponding gray-scale image of the hologram on the spatial light modulator.