The beampath of input radiation in alignment with the longitudinal axis of symmetry of a rectangular parallelepiped laser slab is divided and criss-crossed by a Brewster angle input prism member into two criss-crossing beam path portions fed into the slab input end face for criss-crossing multiple-reflection propagation along the slab to its output end face to be reunited into the single longitudinal-axis-aligned beam by a Brewster angle output prism member adjacent to such output face.
There is provided an optically pumped laser having highly reflective coatings on opposite sides such that multiple reflections of radiation between the reflective coatings of the opposed sides produce lasing in a transverse mode. A plurality of diode lasers mounted in a linear array along the opposed sides with reflective coatings provide pumping emission to the laser. An optical alignment means consisting of prisms receive the stimulating emission from individual diode lasers and align individual stimulating emission such that it is colinear with the reflective radiation within the laser cavity.
5307430 - Abstract - Owned by The United States of America as represented by the United States (Washington, DC)
A lensing duct to condense (intensify) light using a combination of front surface lensing and reflective waveguiding. The duct tapers down from a wide input side to a narrow output side, with the input side being lens-shaped and coated with an antireflective coating for more efficient transmission into the duct. The four side surfaces are uncoated, preventing light from escaping by total internal reflection as it travels along the duct (reflective waveguiding). The duct has various applications for intensifying light, such as in the coupling of diode array pump light to solid state lasing materials, and can be fabricated from inexpensive glass and plastic.
This invention relates to a diode pumped slab laser in the form of a slab where two opposite faces are adapted to receive pumping radiation with the faces being cut at the Brewsters angle at one end to provide entrance/exit faces for the lasing radiation. The laser radiation beam follows a zig-zag path in the slab and is contained within the slab by total internal reflection. The laser slab is contained within an optical cavity which results in the laser beam completing a double zig-zag beam path. The design results in good pump/mode matching, mitigates thermally induced birefringence problems, overcomes amplified spontaneous emission problems, requires no coatings or curved surfaces, and is easy and relatively inexpensive to make. The slab can be used within both Quasi-CW and CW modes.
The present invention is directed to a method for breaking rock and other hard materials using small-charge blasting techniques followed by a mechanical impact breaker. In small-charge blasting techniques, a gas is released into the bottom of a sealed hole located in a free surface of the hard material. The gas pressure rises rapidly in the hole until the gas pressure causes the hard material to fracture. The impact breaker is then used to complete fracturing of the material and to remove the fractured material.
