The present invention provides a way to use anisotropic laser gain media to make a laser that can lase in two longitudinal modes at different wavelengths with orthogonal polarizations. The two longitudinal mode (LM) laser output can be separated to generate two single LM outputs. This type of lasers can also be used to generate low noise continuous wave (CW) harmonics through intracavity harmonic generation.

A method and apparatus for characterizing an optical element. The optical element is part of a laser and is mounted on a translation stage to scan the optical element transverse to an intracavity laser beam. A performance characteristic of the laser is recorded as a function of position of the optical element.

The present application is directed to various architectures of a laser oscillator which include an optical element, reflective, refractive, or diffractive injection device for injection seeding and/or locking a laser oscillator.

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 multi-wavelength laser device equipped with a linear cavity along which a first direction and a second direction opposite to the first direction are defined is disclosed. The apparatus includes, along the first direction, a first optical component, a gain and Raman medium, a sum frequency generation crystal, a first second-harmonic generation crystal and a second optical component. The first optical component allows a pumping light to transmit therethrough and be incident in the first direction. The gain and Raman medium receives the pumping light from the first optical component and generates a first infrared base laser light having a first wavelength and a second infrared base laser light having a second wavelength. The first and second optical components form a laser cavity for oscillation of these two infrared base laser lights. The sum frequency generation crystal receives the first and second infrared base laser lights and generates a first visible laser light having a third wavelength. The first second-harmonic generation crystal receives the first infrared base laser light and generates a second visible laser light having a fourth wavelength. The second optical element allows the first and the second visible laser lights to emit out along the first direction.

Typically, quantum systems are very sensitive to environmental fluctuations, and diagnosing errors via measurements causes unavoidable perturbations. Here, an in situ frequency-locking technique monitors and corrects frequency variations in single-photon sources based on resonators. By using the classical laser fields used for photon generation as probes to diagnose variations in the resonator frequency, the system applies feedback control to correct photon frequency errors in parallel to the optical quantum computation without disturbing the physical qubit. Our technique can be implemented on a silicon photonic device and with sub 1 pm frequency stabilization in the presence of applied environmental noise, corresponding to a fractional frequency drift of <1% of a photon linewidth. These methods can be used for feedback-controlled quantum state engineering. By distributing a single local oscillator across a one or more chips, our approach enables frequency locking of many single photon sources for large-scale photonic quantum technologies.

Apparatus and methods for generating mid-IR frequency combs using intra-pulse DFG. A mode-locked pulse generation laser generates near-IR pulses which are amplified. The amplified pulses are spectrally broadened by a nonlinear element, for example a normal dispersion highly nonlinear fiber (ND-HNLF) to generate broadened pulses. The nonlinear spectral broadening element is a transparent dielectric material having a cubic nonlinear response. Broadened pulses are temporally compressed to generate short, high-power pulses which few-cycle conditioned pulses which are ready for the intrapulse DFG process. The DFG block generates a mid-IR comb by difference frequency generation. It might comprise an orientation patterned GaP (OP-GaP) crystal or a poled lithium niobate (PPLN) crystal.

A method and apparatus for characterizing an optical element. The optical element is part of a laser and is mounted on a translation stage to scan the optical element transverse to an intracavity laser beam. A performance characteristic of the laser is recorded as a function of position of the optical element.

Disclosed is a servo matching control mid-infrared differential dual-wavelength laser based on Nd:MgO:PPLN, The 813 nm semiconductor pumping source, the energy transmitting optical fiber, the first focusing lens, the second focusing lens, the first 45-degree beam splitter, the mid-infrared idle frequency light output mirror, the polarized crystal, the servo motor, the mid-infrared parametric light total reflection mirror, the microprogrammed control unit, the second 45-degree beam splitter, the electro-optical crystal and the 1093 nm fundamental frequency light total reflection mirror are sequentially placed from right to left in a straight cavity of the laser; and the 1084 nm fundamental frequency light total reflection mirror is placed in a bent-shape cavity of the laser, corresponding to a position of the second 45-degree beam splitter, such the second 45-degree beam splitter can reflect incident light to the 1084 nm fundamental frequency light total reflection mirror.

A laser apparatus is provided, which includes an optical reflection and gain unit, an optical modulation unit and a polarizing selection unit. The optical reflection and gain unit includes a gain medium and at least two dichroic surfaces, and is configured to generate a laser beam. The optical modulation unit and the optical reflection and gain unit form a cavity, and the optical modulation unit is configured to adjust phase boundary conditions of the cavity. The optical modulation unit includes portions that respectively correspond to optical phase boundaries in the cavity, so as to allow an optical field in the cavity to pass through the optical modulation unit at least twice. The polarizing selection unit is disposed between the optical reflection and gain unit and the optical modulation unit, and is configured to adjust the polarizing direction of the optical field incident to the optical modulation unit.