The present invention relates to a device and a method for performing overall frequency stabilization of a femtosecond laser optical comb by using optical modes directly extracted from the optical comb, and more particularly, to a device and a method for performing overall frequency stabilization of a femtosecond laser optical comb by using optical modes directly extracted from the optical comb capable of stabilizing an overall range of frequencies of the femtosecond laser optical comb by using optical modes directly extracted from the optical comb and generating a cw laser and pulse having an excellent frequency stability and linewidth from the stabilized optical comb.

A method and system for obtaining single-frequency operation of a laser system. A laser beam is emitted from a laser cavity, having an adjustable length, at a plurality of cavity lengths. At least a portion of the laser beam is received at a detector, which detects the presence of transverse and/or longitudinal modes in the laser beam, and generates a laser beam signal having a beat-note indicative thereof. The laser beam signal for each of the plurality of cavity lengths can be analyzed, and a cavity length of best mode purity, indicating single-frequency operation, can be selected. The laser beam system can emit a laser and have a laser beam splitter for directing at least a portion of the emitted laser beam to a laser beam detector for generating at least one laser beam signal therefrom, and an actuator for adjusting the length of the laser cavity.

The laser system may include a plurality of laser apparatuses, a beam delivery device configured to bundle pulse laser beams emitted from respective laser apparatuses of the plurality of laser apparatuses to emit a bundled pulse laser beam, and a beam parameter measuring device provided in an optical path of the bundled pulse laser beam to measure a beam parameter of each one of the pulse laser beams and a beam parameter of the bundled pulse laser beam.

The present invention relates to a device and a method for performing overall frequency stabilization of a femtosecond laser optical comb by using optical modes directly extracted from the optical comb, and more particularly, to a device and a method for performing overall frequency stabilization of a femtosecond laser optical comb by using optical modes directly extracted from the optical comb capable of stabilizing an overall range of frequencies of the femtosecond laser optical comb by using optical modes directly extracted from the optical comb and generating a cw laser and pulse having an excellent frequency stability and linewidth from the stabilized optical comb.

The laser system may include a delay circuit unit, first and second trigger-correction units, and a clock generator. The delay circuit unit may receive a trigger signal, output a first delay signal obtained by delaying the trigger signal by a first delay time, and output a second delay signal obtained by delaying the trigger signal by a second delay time. The first trigger-correction unit may receive the first delay signal and output a first switch signal obtained by delaying the first delay signal by a first correction time. The second trigger-correction unit may receive the second delay signal and output a second switch signal obtained by delaying the second delay signal by a second correction time. The clock generator may generate a clock signal that is common to the delay circuit unit and the first and second trigger-correction units.

The invention relates to a method for operating a laser device (1), by means of which an optical frequency comb can be stabilized, wherein the frequencies of the modes thereof are describable by the formula f.sub.m=mf.sub.rep+f.sub.0, where f.sub.rep is a mode spacing, f.sub.0 is an offset frequency and m is a natural number. At least one signal (S1, S2, S3, S4) is determined, which correlates with an actual value of a degree of freedom (F), wherein the degree of freedom (F) is a linear combination of the offset frequency f.sub.0 and the mode spacing f.sub.rep of the frequency comb. The actual value of the degree of freedom (F) is set in a predetermined capture range (F) of a second control unit (40) using a first control unit (10) on the basis of the signal. As soon as the capture range (F.sub.capture) of the second control unit (40) is reached, the second control unit (40) is activated and the actual value is regulated to an intended value (F.sub.intended) with the aid of the second control unit (40).

The laser system may include a delay circuit unit, first and second trigger-correction units, and a clock generator. The delay circuit unit may receive a trigger signal, output a first delay signal obtained by delaying the trigger signal by a first delay time, and output a second delay signal obtained by delaying the trigger signal by a second delay time. The first trigger-correction unit may receive the first delay signal and output a first switch signal obtained by delaying the first delay signal by a first correction time. The second trigger-correction unit may receive the second delay signal and output a second switch signal obtained by delaying the second delay signal by a second correction time. The clock generator may generate a clock signal that is common to the delay circuit unit and the first and second trigger-correction units.

The invention relates to an apparatus for generating temporally spaced apart light pulses, comprising a first laser (11) which generates a first sequence (I) of light pulses at a first repetition rate, a second laser (12) which generates a second sequence (II) of light pulses at a second repetition rate, and at least one actuating member which influences the first repetition rate and/or the second repetition rate. It is an object of the invention to provide an apparatus for generating temporally spaced apart light pulses which is improved in relation to the prior art. This object is achieved by the invention by a control element (23) which applies a periodic modulation signal (24) to the actuating member for periodic variation of the first repetition rate and/or the second repetition rate, wherein the actuating member comprises a mechanical oscillator excited by the modulation signal (24), the deflection of said oscillator causing an adjustment in the resonator length of the first laser (11) and/or second laser (12), wherein the mechanical oscillator oscillates in resonant fashion at the frequency of the modulation signal (24). In accordance with the invention, an actuator (e.g. a piezo-actuator) which adjusts the resonator length of the laser is operated in resonant fashion. As a result, a large maximum time offset of the light-pulse sequences (I, II) with, at the same time, a high scanning speed is rendered possible. Moreover, the invention relates to a method for generating temporally spaced apart light pulses.

The invention relates to scanning pulsed laser systems for optical imaging. Coherent dual scanning laser systems (CDSL) are disclosed and some applications thereof. Various alternatives for implementation are illustrated, including highly integrated configurations. In at least one embodiment a coherent dual scanning laser system (CDSL) includes two passively modelocked fiber oscillators. The oscillators are configured to operate at slightly different repetition rates, such that a difference f.sub.r in repetition rates is small compared to the values f.sub.r1 and f.sub.r2 of the repetition rates of the oscillators. The CDSL system also includes a non-linear frequency conversion section optically connected to each oscillator. The section includes a non-linear optical element generating a frequency converted spectral output having a spectral bandwidth and a frequency comb comprising harmonics of the oscillator repetition rates. A CDSL may be arranged in an imaging system for one or more of optical imaging, microscopy, micro-spectroscopy and/or THz imaging.

An electronic circuit for controlling a laser system consisting of a pulse source and high power fiber amplifier is disclosed. The circuit is used to control the gain of the high power fiber amplifier system so that the amplified output pulses have predetermined pulse energy as the pulse width and repetition rate of the oscillator are varied. This includes keeping the pulse energy constant when the pulse train is turned on. The circuitry is also used to control the temperature of the high power fiber amplifier pump diode such that the wavelength of the pump diode is held at the optimum absorption wavelength of the fiber amplifier as the diode current is varied. The circuitry also provides a means of protecting the high power fiber amplifier from damage due to a loss of signal from the pulse source or from a pulse-source signal of insufficient injection energy.