In at least one illustrative embodiment, a laser may include a ceramic body defining a chamber containing a laser gas. The chamber may include first and second slab waveguide sections extending along parallel first and second axes and a third slab waveguide section extending along a perpendicular third axis. Respective first ends of the first and second slab waveguide sections may be positioned adjacent opposite ends of the third slab waveguide section. The laser may also include first and second end mirrors positioned at respective second ends of the first and second slab waveguide sections, a first fold mirror positioned near an intersection of the first and third axes at a 45-degree angle to both the first and third axes, and a second fold mirror positioned near an intersection of the second and third axes at a 45-degree angle to both the second and third axes, such that the first, second, and third slab waveguide sections waveguide recirculating light that is polarized orthogonal to a plane defined by the first, second, and third axes.

The present invention relates to a microdisk laser having characteristics of unidirectional emission and an ultra-high quality factor and also a microdisk laser composed of four circular arcs and configured to emit light in one direction in a resonance mode having the form of a whispering gallery mode formed by total reflection.

The present invention provides a spectral beam combined laser system comprising an optical gain element array, a transform element, a diffraction element and a reflecting element, which are sequentially positioned in an optical path, wherein said optical gain element array comprises a plurality of gain elements radiate laser beams having different wavelength; said transform element focuses and spatially overlaps the laser beams received from said optical gain element array at said diffraction element; said diffraction element diffracts the laser beams spatially overlapped by the transform element to the reflecting element; and said reflecting element feeds back a portion of the laser beams to the optical gain element array in a V-shaped off-axis external cavity with off-axis angle, wherein said V-shaped off-axis external cavity is formed between the reflecting element and the optical gain element array.

A laser system involving coupled distributed resonators disposed serially, with the lasing gain medium located in the main resonator and the output of that resonator being directed into a free space resonator, such that the main resonator output mirror is effectively the free space resonator. The distributed resonators end mirrors are retroreflectors. Interference occurs between light traveling towards the remote mirror of the free space resonator and light reflected therefrom, generating regions of high reflectivity. The coupling of the free space resonator to the regions of high reflectivity of the free space resonator enables the first resonator to lase efficiently, even though the true reflectivity of the main resonator output mirror outside of those regions is insufficient to enable efficient lasing, if at all. This coupled resonator structure enables lasing to occur with a high field of view and the high gain engendered by the high reflectivity regions.

A laser system involving coupled distributed resonators disposed serially, with the lasing gain medium located in the main resonator and the output of that resonator being directed into a free space resonator, such that the main resonator output mirror is effectively the free space resonator. The distributed resonators end mirrors are retroreflectors. Interference occurs between light traveling towards the remote mirror of the free space resonator and light reflected therefrom, generating regions of high reflectivity. The coupling of the free space resonator to the regions of high reflectivity of the free space resonator enables the first resonator to lase efficiently, even though the true reflectivity of the main resonator output mirror outside of those regions is insufficient to enable efficient lasing, if at all. This coupled resonator structure enables lasing to occur with a high field of view and the high gain engendered by the high reflectivity regions.

The present invention provides a spectral beam combined laser system comprising an optical gain element array, a transform element, a diffraction element and a reflecting element, which are sequentially positioned in an optical path, wherein said optical gain element array comprises a plurality of gain elements radiate laser beams having different wavelength; said transform element focuses and spatially overlaps the laser beams received from said optical gain element array at said diffraction element; said diffraction element diffracts the laser beams spatially overlapped by the transform element to the reflecting element; and said reflecting element feeds back a portion of the laser beams to the optical gain element array in a V-shaped off-axis external cavity with off-axis angle, wherein said V-shaped off-axis external cavity is formed between the reflecting element and the optical gain element array.

A laser system involving coupled distributed resonators disposed serially, with the lasing gain medium located in the main resonator and the output of that resonator being directed into a free space resonator, such that the main resonator output mirror is effectively the free space resonator. The distributed resonators end mirrors are retroreflectors. Interference occurs between light traveling towards the remote mirror of the free space resonator and light reflected therefrom, generating regions of high reflectivity. The coupling of the free space resonator to the regions of high reflectivity of the free space resonator enables the first resonator to lase efficiently, even though the true reflectivity of the main resonator output mirror outside of those regions is insufficient to enable efficient lasing, if at all. This coupled resonator structure enables lasing to occur with a high field of view and the high gain engendered by the high reflectivity regions.

The present invention relates to a microdisk laser having characteristics of unidirectional emission and an ultra-high quality factor and also a microdisk laser composed of four circular arcs and configured to emit light in one direction in a resonance mode having the form of a whispering gallery mode formed by total reflection.

An excimer laser includes a chamber for containing a gas mixture between a rear end and a front end of a linear laser resonator, a convex end-mirror defining the rear end, and a plurality of output-coupling mirrors collectively defining the front end. The output-coupling mirrors are distributed along an optical axis of the resonator and have respective normal vectors pointing toward the rear end. The normal vectors include four mutually non-parallel normal vectors, wherein no three of the four mutually non-parallel normal vectors are coplanar. These different orientations of the output-coupling mirrors cooperate with the convex end-mirror to blur fine structure in the output beam of the resonator.

A CO.sub.2 laser that generates laser-radiation in just one emission band of a CO.sub.2 gas-mixture has resonator mirrors that form an unstable resonator and at least one spectrally-selective element located on the optical axis of the resonator. The spectrally-selective element may be in the form of one or more protruding or recessed surfaces. Spectral-selectivity is enhanced by forming a stable resonator along the optical axis that includes the spectrally-selective element. The CO.sub.2 laser is tunable between emission bands by translating the spectrally-selective element along the optical axis.