Solid state lasers emitting at first and a second wavelengths include an additional a conversion amplifier for converting photons having the first wavelength into photons having the second wavelength, thereby improving output efficiency of a preferred wavelength. Erbium lasing materials such as erbium doped garnets and fluorides, are employed, along with the conversion amplifier formed of a transition metal doped II-VI semiconductor, e.g., Cr:ZnSe.

A measurement method includes emitting a transmission signal comprising at least one light pulse, wherein an amplitude of an intensity of the light pulse is modulated with a modulation frequency, detecting a receiving signal comprising at least a part of the transmission signal that is reflected from an external object, selecting at least one frequency component of the receiving signal corresponding to the modulation frequency of the transmission signal, and determining a distance to the external object from a time difference between the emission of the transmission signal and the detection of the selected frequency component of the receiving signal.

An unidirectional short-wave infrared fiber laser, comprising a theta cavity, with a gain unit based on rare-earth cations-doped fiber, the theta cavity having a ring cavity with two additional 2 input ports2 output ports directional couplers DC1 and DC2 inserted therein, one port of the directional coupler DC1 connected to another port of the directional coupler DC2, forming an S-shaped feedback; a band-pass filter to select at a laser wavelength by filtering through transmission inside the theta cavity, the band-pass filter is one of the list comprising a grating-based filter, a Fabry-Perot etalon, and a phase shifted fiber-Bragg grating; and a reflective fiber Bragg grating (FBG) to select the laser wavelength by filtering through reflection inside the theta cavity, the Bragg grating is a notch filter, and the fiber Bragg grating (FBG) is attached to an unused port of the directional coupler DC1 or DC2.

A control method for a line narrowed gas laser apparatus is a control method for a line narrowed gas laser apparatus configured to emit a pulse laser beam including a first wavelength component and a second wavelength component. The apparatus includes a laser chamber including a pair of electrodes, an optical resonator including an adjustment mechanism configured to adjust a parameter of an energy ratio of the first and second wavelength components, and a processor in which relation data indicating a relation of the parameter of the energy ratio with a control parameter of the adjustment mechanism is stored. The control method includes receiving a command value of the parameter of the energy ratio from an external device, and acquiring, based on the relation data, a value of the control parameter corresponding to the command value and controlling the adjustment mechanism based on the value of the control parameter.

A system, apparatus, and method for multiple wavelength Raman interrogation laser generation and Raman spectra acquisition. An intracavity laser tuning subsystem is integrated into the laser cavity. The tuning subsystem allows switching between at least two laser output frequencies in a manner effective for good identification and separation of Raman spectra from non-Raman spectra, including auto-fluorescence from the sample and background. The tuning subsystem can be implemented in different ways in the cavity. It does not require material alteration of the line-narrowing components. Also, processing of acquired raw signal from the multiple wavelength interrogation can further assist effective Raman spectra identification and separation.

A method and a system for measuring an optical asynchronous sample signal. The system for measuring an optical asynchronous sampling signal comprises a pulsed optical source capable of emitting two optical pulse sequences with different repetition frequencies, a signal optical path, a reference optical path, and a detection device. Since the optical asynchronous sampling signal can be measured by merely using one pulsed optical source, the complexity and cost of the system are reduced. A multi-frequency optical comb system using the pulsed optical source and a method for implementing the multi-frequency optical comb are further disclosed.

A laser system comprises a seed module (33) operable to emit a pulse of a first laser beam followed by a pulse of a second laser beam and a plurality of amplification chambers each comprising a gain medium having a gain, wherein the plurality of amplification chambers are arranged to receive the pulse of the first laser beam (45) and amplify the first laser beam in a second order (PA3, PA2, PA1, PA0) and wherein the plurality of amplification chambers are further arranged to receive the pulse of the second laser beam (41) and amplify the second laser beam in a first order (PA0, PA1, PA2, PA3) which is the reverse of the second order. Saturation powers and small signal gain coefficients of the gain media are selected such that the pulse of the first laser beam experiences a total amplification which is less than the total amplification experienced by the pulse of the second laser beam.

A method and a system for measuring an optical asynchronous sample signal. The system for measuring an optical asynchronous sampling signal comprises a pulsed optical source capable of emitting two optical pulse sequences with different repetition frequencies, a signal optical path, a reference optical path, and a detection device. Since the optical asynchronous sampling signal can be measured by merely using one pulsed optical source, the complexity and cost of the system are reduced. A multi-frequency optical comb system using the pulsed optical source and a method for implementing the multi-frequency optical comb are further disclosed.

The invention relates to a laser apparatus comprising a laser radiation source which generates pulsed laser radiation, wherein the laser radiation has spectral components in at least two wavelength ranges that differ from one anothera first wavelength range (W1) and a second wavelength range (W2), and comprising a dispersion control element comprising at least one dielectric multilayer mirror (MCM), wherein the laser radiation is reflected one or more times at the multilayer mirror (MCM). It is an object of the invention to provide a laser apparatus which is improved over the prior art. In particular, the setup thereof should be less complex, require less adjustment outlay andin particularbe less sensitive to external influences. The invention achieves this object in that the multilayer mirror (MCM) is reflective in the two wavelength ranges (W1, W2), the reflection of the spectral component in the second wavelength range (W2) having a time delay in relation to the reflection of the spectral component in the first wavelength range (W1) such that the spectral components of the laser radiation reflected at the multilayer mirror (MCM) in the two wavelength ranges (W1, W2) coincide in time in an interaction centre of the laser apparatus. Moreover, the invention relates to a dielectric multilayer mirror and a method for generating laser radiation.

A microwave-frequency source, generating an output electrical signal at an output frequency f.sub.M, comprises a pump laser source, an optical resonator, and a photodetector. Free spectral range v.sub.FSR of the optical resonator equals an integer submultiple of a Brillouin shift frequency v.sub.B of the optical resonator (i.e., v.sub.B=Mv.sub.FSR). The pump laser source is frequency-locked to a corresponding resonant optical mode of the optical resonator. Pumping the optical resonator with output of the pump laser source at a pump frequency v.sub.pump results in stimulated Brillouin laser oscillation in the optical resonator at respective first, second, and third Stokes Brillouin-shifted frequencies v.sub.1=v.sub.pumpv.sub.B, v.sub.2=v.sub.pump2v.sub.B, and v.sub.3=v.sub.pump3v.sub.B. The photodetector receives stimulated Brillouin laser outputs at the first and third Stokes Brillouin-shifted frequencies v.sub.1 and v.sub.3 and generates therefrom the output electrical signal at a beat frequency f.sub.M=v.sub.1v.sub.3=2v.sub.B. The output electrical signal at the output frequency f.sub.M exhibits exceptionally low phase noise.