# US 10,483,709 B2 · Sub-nanosecond broad spectrum generating laser system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,483,709 B2 - Document ID: US10483709B2 - Status: Granted - Kind: B2 - Application number: 15/764,686 - Filed: 2016-09-22 - Published: 2018-09-27 - Granted: 2019-11-19 - Earliest claimed: 2015-10-06 - Assignees: Ipg Photonics Corporation - Applicants: Ipg Photonics Corporation - Inventors: Igor Moskalev; Sergey Vasilyev; Michael Mirov; Valentin Gapontsev - Web page: https://patentgrep.com/patent/US10483709B2 ## CPC - H01S 3/0092: {Nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity (nonlinear frequency conversion per se G02F1/35)} - G02F 1/3511: {Self-focusing or self-trapping of light; Light-induced birefringence; Induced optical Kerr-effect} - G02F 1/3536: {Four-wave interaction} - G02F 1/3551: {Crystals} - H01S 3/0057: {Temporal shaping, e.g. pulse compression, frequency chirping (soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108)} - H01S 3/0407: {Liquid cooling, e.g. by water} - H01S 3/042: for solid state lasers {(H01S3/0401 takes precedence)} - H01S 3/0619: {Coatings, e.g. AR, HR, passivation layer} - H01S 3/08059: {Constructional details of the reflector, e.g. shape (mirrors in general G02B5/08; mountings for mirrors G02B7/18)} - H01S 3/108: using non-linear optical devices, e.g. exhibiting Brillouin or Raman scattering {(mode locking using a non-linear element H01S3/1112)} - H01S 3/109: Frequency multiplication, e.g. harmonic generation - H01S 3/1112: Passive mode locking - H01S 3/1608: {erbium} - H01S 3/1623: {chromium, e.g. Alexandrite} - H01S 3/1628: {characterised by a semiconducting matrix} - H01S 3/1685: {Ceramics} - H01S 3/2308: {Amplifier arrangements, e.g. MOPA} - G02F 1/3542: {Multipass arrangements, i.e. arrangements to make light pass multiple times through the same element, e.g. using an enhancement cavity} - G02F 2203/11: involving infrared radiation - G02F 2203/26: Pulse shaping; Apparatus or methods therefor - H01S 3/0813: {Configuration of resonator} - H01S 3/094042: {of a fibre laser} - H01S 3/094076: {Pulsed or modulated pumping (H01S3/1024 takes precedence)} - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS ## 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. ## Claims ### Claim 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 (PC) 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. ### Claim 2 (depends on 1) 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. ### Claim 3 (depends on 1) The method of claim 1 further comprising optically superimposing and focusing the signal light and pumping light on the bulk gain medium. ### Claim 4 (depends on 1) 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. ### Claim 5 (depends on 1) 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. ### Claim 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. ### Claim 7 (depends on 6) 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. ### Claim 8 (depends on 6) 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 (PC) 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. ### Claim 9 (depends on 6) 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. ### Claim 10 (depends on 6) 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.