A method for generating light emission is provided. The method includes providing a transistor element including collector, emitter, and base regions, a quantum cascade region between the base and collector regions, and quantum well structures for interband emission within the base or emitter regions. A waveband controller applies, via first and second electrodes with respect to the collector and base regions, a first electrical signal to control a base-collector junction bias level and select between first and second base-collector bias levels. Selection of the first base-collector bias level causes at least one of the emitter and base regions to produce interband-based light emission having a first wavelength of a first wavelength band. Selection of the second base-collector bias level causes the quantum cascade region to produce intraband-based light emission having a second wavelength of a second wavelength band.

A continuous optical beat laser element for generating terahertz (THz) waves and a laser source using same includes periodically poled lithium niobate (ppLN) crystals arranged along a predetermined direction forming a surface generally parallel to the predetermined direction. A Ti diffused region is applied on the surface and an array of gold nanowires are applied on the Ti diffused region to form a gold metal-insulator-metal (MIM) element that optimizes coupling and channeling of THz radiation from the crystals into the gold nanowires. The system provides a simple, stable, compact and cost-effective THz source using a widely tunable C-band SOA-based laser to excite a non-linear photo-mixer to produce terahertz radiation that ranges from 0.8 to 2.51 THz at room temperature. This laser source can be modified into an all fiber-based THz generator by embedding ppLN crystals in a fiber filament configuration resulting in less absorption and producing high output power.

A fiber laser producing a beam of ultrashort laser pulses at a repetition rate greater than 200 MHz includes a linear fiber resonator and a fiber branch. Ultrashort laser pulses are generated by passive mode-locking and circulate within the linear fiber resonator. Each circulating laser pulse is split into a portion that continues propagating in the linear fiber resonator and a complementary portion that propagates through the fiber branch and is then returned to the linear fiber resonator. The optical length of the linear fiber resonator is an integer multiple of the optical length of the fiber branch. The repetition rate of the ultrashort laser pulses is the reciprocal of the propagation time of the laser pulses through the fiber branch.

A laser oscillator includes: an external resonator configured to include laser media to emit laser beams having different wavelengths; and a partially reflective mirror to transmit part of the laser beams and reflect and return a remainder toward the laser media. The external resonator includes therein: a diffraction grating to perform wavelength coupling on the laser beams having different wavelengths emitted from the laser media so as to superimpose the laser beams into one laser beam and to emit, to the partially reflective mirror, the one laser beam; and a prism that is placed between the laser media and the diffraction grating and that superimposes the laser beams into one laser beam on the diffraction grating, the prism including two surfaces forming an apex angle, one of the two surfaces being an incident surface and another of the two surfaces being an exit surface.

Narrow-optical linewidth laser generation devices and methods for generating a narrow-optical linewidth laser beam are provided. One narrow-optical linewidth laser generation devie includes a single-wavelength mirror or multiwavelength mirror (for comb lasers) formed from one or more optical ring resonators coupled with an optical splitter. The optical splitter may in turn be coupled with a quantum dot optical amplifier (QDOA), itself coupled with a phase-tuner. The phase tuner may be further coupled with a broadband mirror. The narrow-optical linewidth laser beam is generated by using a long laser cavity and additionally by using an integrated optical feedback.

An external optical feedback element (108) for tuning an output beam of a gas laser (102) having multiple wavelengths includes a partially reflective optical element (108) positioned on a beam path of the output beam (106) outside of an internal optical cavity of the gas laser (102), and a stage (114) to support the optical element and adjust rotation, horizontal tilt angle, and vertical tilt angle of the optical element with respect to the beam path. The output beam (106) is partially reflected at the optical element (108) and fed back into the internal optical cavity of the gas laser (102), with the intensity varying for multiple wavelengths and adjusted by changing rotation, horizontal tilt angle and vertical tilt angle of the optical element. Thereby, a variable feedback of the output beam into the internal optical cavity of the gas laser is provided, which leads to a selective output wavelength of the gas laser, either at a single line or at multiple lines simultaneously. This setup may allow to control the wavelength of a commercial CO2 gas laser without a modification of the laser itself by adding a coupled cavity with a wavelength selective element like a grating to the given gas laser resonator.

A device for combining at least two input laser beams having different spectral components. At least one pre-compensation unit for the at least two input laser beams has a diffractive optical unit which expands the input laser beam into an intermediate beam bundle in which the spectral components are spatially arranged so as to be adjacent to one another with increasing wavelength. A combination unit has at least a first diffractive optical element and a second diffractive optical element, the combination unit being aligned with the pre-compensation unit in such a way that the first diffractive optical element converts an intermediate beam bundle into a convergent beam bundle having a beam waist, the beam waist lying on the second diffractive element, and the second diffractive optical element being designed in this way that all incident spectral components are diffracted in a common radiation direction.

A system and method for stabilizing and combining multiple emitted beams into a single system using both WBC and WDM techniques.

The present invention is related to laser technology which enables efficient, passive, coherent beam combination from distributed gain sources. The present invention includes a novel architecture which coherently combines the power from multiple sources, and which adds considerable flexibility to laser gain materials for many applications. The novel architecture of the present invention combines two techniques: 1) beam splitting and combination; and 2) phase-locking (i.e., maintaining a common phase relationship between multiple beams), using reflective gratings. Thus, the present invention addresses important limitations in laser technology: efficiency, power scaling and wavelength selectivity.

A system and method for stabilizing and combining multiple emitted beams into a single system using both WBC and WDM techniques.