Provided are a Ga.sub.2O.sub.3-based single crystal substrate including a Ga.sub.2O.sub.3-based single crystal which has a high resistance while preventing a lowering of crystal quality and a production method therefor. According to one embodiment of the present invention, the production method includes growing the Ga.sub.2O.sub.3-based single crystal while adding a Fe to a Ga.sub.2O.sub.3-based raw material, the Ga.sub.2O.sub.3-based single crystal (5) including the Fe at a concentration higher than that of a donor impurity mixed in the Ga.sub.2O.sub.3-based raw material, and cutting out the Ga.sub.2O.sub.3-based single crystal substrate from the Ga.sub.2O.sub.3-based single crystal (5).

In some embodiments, a selective cyclic (optionally dry) etching of a first surface of a substrate relative to a second surface of the substrate in a reaction chamber by chemical atomic layer etching comprises forming a modification layer using a first plasma and etching the modification layer. The first surface comprises carbon and/or nitride and the second surface does not comprise carbon and/or nitride.

A method of manufacturing graphene, the method including: preparing a carrier member on which the graphene is formed on one surface thereof; exposing the graphene to dopant vapor to dope the graphene; transferring the doped graphene onto a target member; and removing the carrier member.

Using processes disclosed herein, materials and structures are created and used. For example, processes can include melting boron nitride or amorphous carbon into an undercooled state followed by quenching. Exemplary new materials disclosed herein can be ferromagnetic and/or harder than diamond. Materials disclosed herein may include dopants in concentrations exceeding thermodynamic solubility limits. A novel phase of solid carbon has structure different than diamond and graphite.

Provided are a Ga.sub.2O.sub.3-based single crystal substrate including a Ga.sub.2O.sub.3-based single crystal which has a high resistance while preventing a lowering of crystal quality and a production method therefor. According to one embodiment of the present invention, the production method includes growing the Ga.sub.2O.sub.3-based single crystal while adding a Fe to a Ga.sub.2O.sub.3-based raw material, the Ga.sub.2O.sub.3-based single crystal (5) including the Fe at a concentration higher than that of a donor impurity mixed in the Ga.sub.2O.sub.3-based raw material, and cutting out the Ga.sub.2O.sub.3-based single crystal substrate from the Ga.sub.2O.sub.3-based single crystal (5).

A method of performing spatial separation of different wavelengths in a single laser cavity includes generating, from a pump radiation source, pump radiations in spatially separate channels and focusing the generated pump radiations in the spatially separate channels towards an active gain medium having amplification spectra. The method also includes emitting from the active gain medium, amplified radiations of the spatially separate channels, each channel of the spatially separate channels representing a corresponding wavelength and focusing the emitted amplified radiations of the spatially separated channels towards an aperture. The method further includes suppressing, at the aperture, an off-axis mode of the amplified radiations of the spatially separate channels, diffracting the amplified radiations of the spatially separate channels received through the aperture to provide diffracted radiations and returning a portion of the diffracted radiations back to the aperture, and collimating the diffracted radiations of the spatially separate channel.

A method of performing spatial separation of different wavelengths in a single laser cavity includes generating, from a pump radiation source, pump radiations in spatially separate channels and focusing the generated pump radiations in the spatially separate channels towards an active gain medium having amplification spectra. The method also includes emitting from the active gain medium, amplified radiations of the spatially separate channels, each channel of the spatially separate channels representing a corresponding wavelength and focusing the emitted amplified radiations of the spatially separated channels towards an aperture. The method further includes suppressing, at the aperture, an off-axis mode of the amplified radiations of the spatially separate channels, diffracting the amplified radiations of the spatially separate channels received through the aperture to provide diffracted radiations and returning a portion of the diffracted radiations back to the aperture, and collimating the diffracted radiations of the spatially separate channel.

A method of performing spatial separation of different wavelengths in a single laser cavity includes generating, from a pump radiation source, pump radiations in spatially separate channels and focusing the generated pump radiations in the spatially separate channels towards an active gain medium having amplification spectra. The method also includes emitting from the active gain medium, amplified radiations of the spatially separate channels, each channel of the spatially separate channels representing a corresponding wavelength and focusing the emitted amplified radiations of the spatially separated channels towards an aperture. The method further includes suppressing, at the aperture, an off-axis mode of the amplified radiations of the spatially separate channels, diffracting the amplified radiations of the spatially separate channels received through the aperture to provide diffracted radiations and returning a portion of the diffracted radiations back to the aperture, and collimating the diffracted radiations of the spatially separate channel.

A method of fabrication of laser gain material and utilization of such media includes the steps of introducing a transitional metal, preferably Cr.sup.2+ thin film of controllable thickness on the ZnS crystal facets after crystal growth by means of pulse laser deposition or plasma sputtering, thermal annealing of the crystals for effective thermal diffusion of the dopant into the crystal volume with a temperature and exposition time providing the highest concentration of the dopant in the volume without degrading laser performance due to scattering and concentration quenching, and formation of a microchip laser either by means of direct deposition of mirrors on flat and parallel polished facets of a thin Cr:ZnS wafer or by relying on the internal reflectance of such facets.

A method of fabrication of laser gain material and utilization of such media includes the steps of introducing a transitional metal, preferably Cr.sup.2+ thin film of controllable thickness on the ZnS crystal facets after crystal growth by means of pulse laser deposition or plasma sputtering, thermal annealing of the crystals for effective thermal diffusion of the dopant into the crystal volume with a temperature and exposition time providing the highest concentration of the dopant in the volume without degrading laser performance due to scattering and concentration quenching, and formation of a microchip laser either by means of direct deposition of mirrors on flat and parallel polished facets of a thin Cr:ZnS wafer or by relying on the internal reflectance of such facets.