The invention relates to an optical resonator (1) for a laser device (20), in particular for a microchip solid-state laser, comprising an optical medium (4) which is arranged between a first and a second reflective element (2, 3) that are arranged at a distance from one another in a longitudinal direction (P). The optical resonator length is specified by the distance from the first reflective element (2) to the second reflective element (3) in the longitudinal direction (P), the longitudinal extent of the medium (4) arranged between the reflective elements, and the refractive index thereof. According to the invention, the optical resonator length varies in at least one lateral direction (L) running perpendicularly to the longitudinal direction (P). The invention further relates to a laser device (20) comprising such a resonator (1) and to a method for adjusting the laser device (20).

A laser device including a first cavity forming a Mamyshev oscillator, comprising a bandpass first filter at the first wavelength, and a second filter that also transmits the wavelength but that is reflective at a second wavelength, a second cavity, containing the first cavity, for forming a continuous-wave laser beam at the first wavelength and/or at a third wavelength neighbouring the first wavelength, the separation between the first and third wavelengths being smaller than the spectral width of the first filter and of the second filter, and means for allowing or interrupting a continuous-wave oscillation at the first wavelength or at said neighbouring wavelength, in the second cavity.

There are provided: a planar waveguide in which claddings (2) and (3) each having a smaller refractive index than a laser medium for absorbing pump light (5) are bonded to an upper surface (1a) and a lower surface (1b) of a core (1) which is formed from the laser medium; pump light generation sources (4a) and (4b) for emitting pump light (5) to side surfaces (1c) and (1d) of the core (1); and laser light high reflection films (6a) and (6b) formed on side surfaces (1e) and (1f) of the core (1). Each of side surfaces (2e) and (2f) of the cladding (2) corresponding to the side surfaces (1e) and (1f) of the core (1) has a ridge structure (20) in which a part thereof is recessed.

There are provided: a planar waveguide in which claddings (2) and (3) each having a smaller refractive index than a laser medium for absorbing pump light (5) are bonded to an upper surface (1a) and a lower surface (1b) of a core (1) which is formed from the laser medium; pump light generation sources (4a) and (4b) for emitting pump light (5) to side surfaces (1c) and (1d) of the core (1); and laser light high reflection films (6a) and (6b) formed on side surfaces (1e) and (1f) of the core (1). Each of side surfaces (2e) and (2f) of the cladding (2) corresponding to the side surfaces (1e) and (1f) of the core (1) has a ridge structure (20) in which a part thereof is recessed.

Disclosed is an injected laser including an optical amplifying medium arranged inside a triggered laser cavity, the optical amplifying medium having a spectral amplifying band. The injected laser includes an optical phase-modulation device, arranged between the injection source and the laser cavity, the optical phase-modulation device being configured to periodically modulate as a function of time a phase of the monochromatic continuous laser radiation at a modulation frequency equal to a natural integer multiple of the free spectral range of the laser cavity, so that the phase-modulated injection source generates a polychromatic injection radiation.

In a semiconductor laser, a block layer is provided on both sides of a mesa-type semiconductor part having an n-type cladding layer, an active layer, and a p-type cladding layer. The block layer has: a p-type block layer formed on the side surface of the mesa-type semiconductor part and over a p-type semiconductor substrate; a high-resistance layer formed over the p-type block layer; and an n-type block layer formed over the high-resistance layer, which has a higher resistance than that of the p-type block layer. By providing the high-resistance layer between the p-type block layer and the n-type block layer, the thickness of the p-type block layer can be controlled and a leakage current (flow of a hole) can be reduced. Further, the distance between the n-type cladding layer and the n-type block layer can be secured, and hence a leakage current (flow of an electron) can be prevented.

In one exemplary embodiment, an apparatus can be provided which includes at least one biological medium that causes gain. According to another exemplary embodiment, an arrangement can be provided which is configured to be provided in an anatomical structure. This exemplary arrangement can include at least one emitter having a cross-sectional area of at most 10 microns within the anatomical structure, and which is configured to generate at least one laser radiation. In a further exemplary embodiment, an apparatus can be provided which can include at least one medium which is configured to cause gain; and at least one optical biological resonator which is configured to provide an optical feedback to the medium. In still another exemplary embodiment, a process can be whereas, a solution of an optical medium can be applied to a substrate. Further, it is possible to generate a wave guide having a shape that is defined by (i) at least one property of the solution of the optical medium, or (ii) drying properties thereof.

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.

An injection-seeded whispering gallery mode optical amplifier. The amplifier includes a micro or nanoscale whispering gallery mode resonator configured to amplify a whispering gallery mode therein via a gain medium separated from the whispering gallery mode resonator but within the evanescent field of the whispering gallery mode resonator. A pump stimulates the whispering gallery mode. A plasmonic surface couples power into the whispering gallery mode resonator.

The present invention discloses an elliptical cladding polarization-maintaining large-mode-area gain fiber, structurally comprising a core of the elliptical cladding polarization-maintaining large-mode-area gain fiber, an inner cladding, an elliptical stress layer, a first outer cladding, a second outer cladding and a third outer cladding, wherein the inner cladding surrounds the core; the elliptical stress layer surrounds the inner cladding, and has an elliptical cross-sectional shape; the first outer cladding surrounds the elliptical stress layer; the second outer cladding surrounds the first outer cladding; and the third outer cladding surrounds the second outer cladding. As the birefringence of the elliptical cladding polarization-maintaining fiber is directly proportional to the ellipticity and the deposition of a stress-applying area occurs during the preform rod forming process, procedures of preform drilling and the like are eliminated, and the likelihood of preform contamination is greatly reduced. The optical loss and strength of the fiber can hence be improved, and the entire manufacturing process is simplified. Furthermore, the birefringence and the pump absorption of the fiber can also be improved.