Method and system for generation of optical pulses of light
A laser system for the generation of ultrashort optical pulses of light including an oscillator emitting low power and negatively chirped optical pulses with a spectral bandwidth W 1, a dispersive connecting segment to maintain the sign of the chirp of the pulses of the oscillator, an optical amplifier for amplifying the optical light pulses and a negative group velocity dispersion segment for compensating phase contributions of the whole propagation process. During the propagation from the output of the oscillator to the end of the optical amplifier, the chirp of the light pulses will change once from negative to positive chirp. After a final compression stage ultrashort optical pulses can be generated.
1 . A laser system comprising:
an oscillator producing a plurality of negatively chirped optical pulses having a first spectral width W 1 ;
an amplifier for receiving the plurality of optical pulses and amplifying the plurality of optical pulses to produce at an output of the amplifier an optical light pulse having a second spectral width W 2 ; and
a positive group velocity dispersion connecting segment connected directly between the oscillator and an input of the amplifier, wherein the connecting segment is adapted to maintain the sign of the chirp of the plurality of optical pulses; and wherein the sign of the chirp is changed between the oscillator and the output of the amplifier.
2 . The laser system of claim 1 , wherein the second spectra width W 2 at the output of the amplifier is greater than the first spectral width WI of the oscillator.
3 . The laser system of claim 1 , wherein the connecting segment has a positive group velocity dispersion (β 2 >0) without changing the sign of the chirp.
4 . The laser system of claim 1 , wherein the connecting segment is adapted to change the amount of the chirp.
5 . A laser system comprising:
an oscillator producing a plurality of negatively chirped optical pulses having a first spectral width W 1 ;
an amplifier for receiving the plurality of optical pulses and amplifying the plurality of optical pulses to produce at an output of the amplifier an optical light pulse having a second spectral width W 2 ;
a positive group velocity dispersion connecting segment connected directly between the oscillator and an input of the amplifier, wherein the connecting segment is adapted to maintain the sign of the chirp of the plurality of optical pulses; and wherein the sign of the chirp is changed between the oscillator and the output of the amplifier; and
a second segment of positive group velocity dispersion segment (β 2 ) connected to an output of the amplifier.
6 . The laser system of claim 1 , further comprising a negative group velocity dispersion segment (β 2 ) connected to an output of the amplifier and being adapted to compensate the phase contributions of linear and nonlinear effects that have occurred during propagation through the connecting segment and the optical amplifier including the phase of the optical pulse.
7 . The laser system of claim 1 , wherein the amplifier is one of a fiber amplifier, a rod-type amplifier, a slab amplifier, thin disk amplifier or a solid-state amplifier.
8 . The laser system of claim 1 , wherein the connecting segment is a combination of positive group velocity dispersion (β 2 ) and negative group velocity dispersion segments (β 2 ) without changing the sign of the chirp.
9 . The laser system of claim 1 , further comprising at least one optical isolator located after the oscillator.
10 . The laser system of claim 9 , wherein the optical isolator is one of a free space or fiber coupled.
11 . The laser system of claim 1 , further including at least one of a pre-amplifier or an attenuator within the connecting segment.
12 . The laser system of claim 11 , wherein the preamplifier is one of a fiber-based amplifier, a semiconductor optical amplifier or a solid-state amplifier.
13 . The laser system of claim 1 , further including at least an optical pulse picker to adjust the temporal separation between the optical pulses.
14 . The laser system of claim 1 , wherein the oscillator comprises at least a segment of positive group velocity dispersion (β 2 ) and a segment of negative group velocity dispersion (β 2 ).
15 . The laser system of claim 1 , wherein the laser active medium of at least one of the oscillator or the amplifier ( 50 ) is selected from the group of dopants comprising Yb, Nd, Tm, or Er.
16 . The laser system ( 10 ) of claim 1 , wherein the oscillator ( 20 ) comprises a linear cavity with a saturable absorber at one end and a grating compressor at the other end.
17 . The laser system of claim 1 , wherein the amplifier is pumped by at least one of a single mode diode laser or multi-mode laser.
18 . The laser system of claim 1 , wherein the oscillator and amplifier are one of a single clad fiber or a double clad fiber or a combination of these.
19 . The laser system of claim 1 , wherein the amplifier comprises a chirp-free point at which, in use, the chirp of the optical pulses is substantially reduced to zero, wherein at the output of the optical amplifier, the optical pulses are positively chirped.
20 . A laser system comprising:
an oscillator producing a plurality of negatively chirped optical pulses having a first spectral width W 1 ;
an amplifier for receiving the plurality of optical pulses and amplifying the plurality of optical pulses to produce at an output of the amplifier an optical light pulse having a second spectral width W 2 ; and
a positive group velocity dispersion connecting segment connected directly between the oscillator and an input of the amplifier, wherein the connecting segment is adapted to maintain the sign of the chirp of the plurality of optical pulses; and wherein the sign of the chirp is changed between the oscillator and the output of the amplifier;
wherein at an output of the laser system a third spectral width is generated, in use, by shifting the chirp-free point to the end of the amplifier.