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.

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.

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 for generating an electromagnetic useful radiation having a useful frequency is provided and includes generating and radiating an electromagnetic pump radiation with a pump frequency, coupling the pump radiation into an external optical resonator having a resonance frequency. The resonance frequency is at least initially substantially equal to the pump frequency, such that resonator electromagnetic radiation oscillates in the resonator at the resonance frequency. The method further includes temporally, after coupling the pump radiation, changing the resonance frequency of the resonator so that the resonance frequency of the resonator radiation oscillating in the resonator is changed over a tuning bandwidth, wherein the pump frequency does not follow the change in resonance frequency, decoupling of the resonator radiation as useful radiation with the useful frequency different from the pump frequency from the resonator, pumping of an amplifying medium arranged in the resonator; and amplifying the resonator radiation oscillating in the resonator in the amplifying medium. The amplification is smaller than a threshold amplification required by the resonator and the amplifying medium for a laser action of the resonator.

A high repetition rate pulse laser including a linear cavity having a first direction and a second direction opposite to the first direction is disclosed. The pulse laser includes, along the first direction, a first optical component, a gain and Raman medium, an acousto-optic crystal, a first lithium triborate (LBO) crystal and a second optical component. The first optical component allows a pumping light incident in the first direction to transmit therethrough. 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 acousto-optic crystal receives a radio frequency control signal from a radio frequency controller, wherein the radio frequency control signal has a signal period including a low level period and a high level period.

The invention discloses a visible laser apparatus including a linear cavity. The linear cavity includes along the first direction: a first optical component, a gain medium, a second optical component, a Raman crystal, a double-harmonic crystal and a third optical component. The first optical component receives an incident pumping light in the first direction. The gain medium receives the pumping light from the first optical component, and generates a first infrared base laser having a first wavelength. The second optical component has a first high transmittance in a first wave band including the first wavelength in the first and the second directions. The Raman crystal receives the first infrared base laser, and generates a second infrared base laser having a second wavelength. The double-harmonic crystal receives the first and the second infrared base lasers, and generates a visible laser light having a third wavelength.

A high repetition rate pulse laser including a linear cavity having a first direction and a second direction opposite to the first direction is disclosed. The pulse laser includes, along the first direction, a first optical component, a gain and Raman medium, an acousto-optic crystal, a first lithium triborate (LBO) crystal and a second optical component. The first optical component allows a pumping light incident in the first direction to transmit therethrough. 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 acousto-optic crystal receives a radio frequency control signal from a radio frequency controller, wherein the radio frequency control signal has a signal period including a low level period and a high level period.

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.

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.

A laser device for laser detection and ranging (LiDAR), comprising: a laser oscillator configured for emitting a pulsed laser beam, a laser beam amplifier disposed on the laser beam path, a pumping unit disposed between the laser oscillator and the laser beam amplifier and configured to, when receiving an incoming continuous pumping beam having the pumping wavelength, transmit the laser beam along the laser direction; send the pumping beam for pumping the laser oscillator in the opposite directions to the laser direction, and transmit a reflected part of the pumping beam for pumping the laser beam amplifier, in the laser direction.