Sub-nanosecond broad spectrum generating laser system

Patent metadata

Field	Value
Publication number	US-10483709-B2
Application number	US-201615764686-A
Country	US
Kind code	B2
Filing date	Sep 22, 2016
Priority date	Oct 6, 2015
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

The present invention provides systems and methods for producing short laser pulses that are amplified and spectrally broadened in a bulk gain media. The bulk material, having laser gain and nonlinear properties, is concurrently exposed to an optical pump input and a seed input, the pump power being sufficient to amplify and spectrally broaden the seed pulse.

First claim

The invention claimed is:

1. A method of enhancing properties of sub-nanosecond pulses comprising:
coupling pulsed signal light at a first wavelength into a bulk gain medium, thereby guiding input sub-nanosecond pulses of the signal light through the bulk gain medium in a single pass, wherein each input sub-nanosecond pulse of the signal light has a first pulse duration, first spectral width and first pulse peak power; and
coupling pump light at a second wavelength, which is different from the first wavelength, into the bulk gain medium while guiding the sub-nanosecond pulses there through, thereby outputting sub-nanosecond pulses at the first wavelength such that each output sub-nanosecond pulse has a:
second pulse duration shorter than the first pulse duration,
second spectral width broader than the first spectral width, and
second pulse peak power higher than the first pulse peak power; and

generating the signal light by pico- or femtosecond TM:II-VI lasers prior to the coupling of the input sub-nanosecond pulses into the bulk gain medium such that the first peak power of the sub-nanosecond pulses at least equals to a critical power (P C ) for self-focusing in the bulk gain medium, the bulk gain medium being selected from TM:II-VI nanocrystals or polycrystals which are made from Cr:ZnS, Cr:ZnSe, Cr:CdS, Fe:ZnSe or Fe:ZnS.

2. The method of claim 1 , wherein the pumping of the bulk gain medium includes a continuous wave pumping or pulsed pumping by a pump fiber laser which is selected from Er- or Tm-doped fiber lasers or TM:II-VI lasers.

3. The method of claim 1 further comprising optically superimposing and focusing the signal light and pumping light on the bulk gain medium.

4. The method of claim 1 , wherein the guiding of the input sub-nanosecond pulses through the bulk gain medium includes interacting between the input sub-nanosecond pulses and bulk medium, thereby producing a nonlinear effect which includes self-focusing, self-phase modulation, cross-phase modulation, or four-wave mixing or a combination thereof.

5. The method of claim 1 further comprising optically separating the output sub-nanosecond pulses of the signal light and pump light, wherein the sub-nanosecond pulses include femtosecond or picosecond pulses.

6. A sub-nanosecond, broad spectrum generating laser system comprising:
a master oscillator emitting pulsed signal light of input sub-nanosecond pulses along a path at a first wavelength, the input sub-nanosecond pulses each having a first pulse duration, first spectral width and first pulse peak power;
a nonlinear bulk gain medium downstream from the master oscillator;
an optical pump emitting continuous or discontinuous light pump at a second wavelength different from the first wavelength; and
an input optical assembly between the master oscillator and nonlinear bulk gain medium, the input optical assembly being configured to superimpose and focus the pulsed signal and pump light on the bulk gain medium in a single pass such that the nonlinear bulk gain medium outputs sub-nanosecond pulses at the first wavelength, wherein each output sub-nanosecond pulse has a:
second pulse duration shorter than the first pulse duration,
second spectral width broader than the first spectral width, and

second pulse peak power higher than the first pulse peak power; and
wherein the nonlinear bulk gain medium includes TM:II-VI nanocrystals or polycrystals made form one of Cr:ZnS, Cr:ZnSe, Cr:CdS, Fe:ZnSe or Fe:ZnS.

7. The laser system of claim 6 further comprising an output optical assembly configured to separate the output sub-nanosecond pulses from the pump light downstream from the nonlinear bulk gain medium.

8. The laser system of any of claim 6 , wherein the master oscillator is operative to generate the input sub-nanosecond pulses each with a peak power at least equal to critical power (P C ) for producing a nonlinear effect in the nonlinear bulk gain medium which includes one of self: focusing, self-phase modulation, cross-phase modulation, four-wave mixing, filamentation, pulse compression or a combination of these.

9. The laser system of claim 6 , wherein the optical pump is selected from Er-, Tm-doped fiber lasers or TM:II-VI lasers, the master oscillator being selected from pica- or femtosecond TM:II-VI lasers.

10. The laser system of claim 6 further comprising at least one dispersive element located upstream or downstream from the nonlinear bulk gain medium, the dispersive element being one of a plane-parallel plate, a set of dispersive prisms, dispersive mirrors, or a combination of the these, the dispersive element being configured to control parameters of the input sub-nanosecond pulses.

Assignees

• Ipg Photonics Corp

Inventors

• Moskalev Igor
• Vasilyev Sergey
• Mirov Michael
• Gapontsev Valentin

Classifications

• H01S3/1685

  Ceramics · CPC title

• H01S3/1623

  chromium, e.g. Alexandrite · CPC title

• H01S3/0813

  Configuration of resonator · CPC title

• G02F1/3536

  Four-wave interaction · CPC title

• H01S3/094076

  Pulsed or modulated pumping (H01S3/1024 takes precedence) · CPC title