A method of emitting photons at a desired wavelength, including: providing a material having a first region of high absorption of radiation at a first set of wavelength of radiation, contiguous with a second region of low absorption of radiation at a shorter set of wavelengths, and a third region of high emission at a further shorter set of wavelengths; applying energy to the material at the first region, such that most of an effective black body radiation of said material at a temperature of the material would fall within the second region and be configured to transfer energy to said third region and not overlap with the first region; and emitting energy from the material at the third region, powered by said applying energy.

A photonic molecule laser is described that includes a photonic molecule waveguide coupled to a photonic molecule seeding source configured to deliver a plurality of photonic molecules. The photonic molecule waveguide includes a second dopant maintained at a population inverted state with an energy level transition corresponding to a second frequency that is an N-fold multiple of a first frequency and amplifies the number of photonic molecules via stimulated emission. The photonic molecule seeding source includes a waveguide with a first dopant maintained at a population inverted state with an energy level transition corresponding to the first frequency. A pump source is coupled to the waveguide configured to deliver a first frequency laser pulse with pulse coherence time less than the photonic molecules correlation time. Each photonic molecule includes a threshold bound state of N first frequency photons, and each photonic molecule has the second frequency.

High-power, highly efficient 3-level system fiber lasers are described. The lasers can operate at an average power of about 50W or greater with an efficiency of about 60% or greater with low diffraction limited mode quality. The lasers incorporate an all-solid photonic bandgap fiber that includes a large core (20 micrometers or greater), a high core/clad ratio (greater than 15%), and a waveguide cladding designed to define a transmission band to suppress the 4-level system of the gain medium through determination of the node size of individual nodes of a cladding lattice.

Fiber lasers and methods are provided, in which the modal instability threshold is raised to provide more laser power. Fiber lasers comprise an active optical fiber having at least one absorption peak wavelength (.sub.peak) and capable of supporting more than a fundamental mode during operation, and a plurality of pump diodes connected to deliver radiation emitted thereby into the optical fiber. At least one of the pump diodes is a wavelength-locked (WL) diode and at least one of the pump diodes is configured to deliver radiation at at least (not necessarily the same diode(s)). The pump diodes may comprise any of WL diode(s) at .sub.peak, WL diode(s) at =.sub.peak and non-WL diode(s). Pumping radiation off the fiber's absorption peak increases the modal instability threshold, most likely by reducing the temperature gradient in the active fiber at the fiber pump entrance point and along the fiber.

A multi-clad optical fiber design is described in order to provide low optical loss, a high numerical aperture (NA), and high optical gain for the fundamental propagating mode, the linearly polarized (LP) 01 mode in the UV and visible portion of the optical spectrum. The optical fiber design may contain dopants in order to simultaneously increase the optical gain in the core region while avoiding additional losses during the fiber fabrication process. The optical fiber design may incorporate rare-earth dopants for efficient lasing. Additionally, the modal characteristics of the propagating modes in the optical core promote highly efficient nonlinear mixing, providing for a high beam quality (M.sup.2<1.5) output of the emitted light.

Laser waveguides, methods and systems for forming a laser waveguide are provided. The waveguide includes an inner cladding layer surrounding a central axis and a glass core surrounding and located outside of the inner cladding layer. The glass core includes a laser-active material. The waveguide includes an outer cladding layer surrounding and located outside of the glass core. The inner cladding, outer cladding and/or core may surround a hollow central channel or bore and may be annular in shape.

An optical element is provided. The optical element may comprise a material, the material being a matrix and a set of particles included in the matrix, the material having a molar fraction of SiO.sub.2 higher than or equal to 65 percent, each particle having a dimension smaller than or equal to 80 nanometers.

Laser waveguides, methods and systems for forming a laser waveguide are provided. The waveguide includes an inner cladding layer surrounding a central axis and a glass core surrounding and located outside of the inner cladding layer. The glass core includes a laser-active material. The waveguide includes an outer cladding layer surrounding and located outside of the glass core. The inner cladding, outer cladding and/or core may surround a hollow central channel or bore and may be annular in shape.

Systems and methods for end pumped laser mirror stack assemblies are provided. In one embodiment, an end pump mirror stack assembly for a laser resonator comprises: a pump light injection layer applied to a transparent substrate, the pump light injection layer comprising at least one light generating optical emitter embedded within the pump light injection layer, wherein the pump light injection layer is configured to transmit a pump light having a first wavelength into the substrate; a multilayer thin-film mirror stack coupled to the transparent substrate; a lasing material layer coupled transparent substrate and positioned to receive the pump light, wherein the lasing material layer is doped with a dopant that generates a fluorescent light output at a second frequency when exposed to the pump light; and an antireflective coating applied to the substrate, the first anti-reflective coating configured to pass light of the first wavelength.

A solid state ring laser gyroscope comprises a laser block including a resonant ring cavity having an optical closed loop pathway; a plurality of mirror structures mounted on the block and including respective multilayer mirrors that reflect light beams around the closed loop pathway; and a pump laser assembly in optical communication with the closed loop pathway through one of the mirror structures. One or more of the multilayer mirrors includes a rare-earth doped gain layer operative to produce bidirectional optical amplification of counter-propagating light beams in the closed loop pathway. In some embodiments, the gain layer comprises a rare-earth dopant other than neodymium that is doped into a glassy host material comprising titania, tantalum oxide, alumina, zirconia, silicate glass, phosphate glass, tellurite glass, fluorosilicate glass, or non-oxide glass. Alternatively, the gain layer can comprise a neodymium dopant that is doped into a glassy host material other than silica.