Low-threshold supercontinuum generation in bulk dielectrics and semiconductors
AssigneeIpg Photonics Corporation
InventorsSergey Vasilyev, Mike Mirov, Igor Moskalev
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Abstract
Controlling a low-threshold femtosecond supercontinuum (fs SCG) in a bulk nonlinear material (BNLM) with a positive thermo-optic coefficient (dn/dT>0 K−1) is provided by coupling light at a first wavelength output by a fs oscillator at a full pulse repetition PRR into the BNLM. The coupling of light produces a nonlinear lens of the coupled beam in the BNLM which is insufficient to provide intensity of the light sufficient to reach ta threshold of the fs SCG. To raise the pulse energy and reach the SCG threshold, light at a second wavelength different from the first wavelength is absorbed in the BNLM to form a thermal lens in the BNLM which assist the nonlinear lens in creating the SCG.
Claims20
A method of controlling femtosecond supercontinuum (fs SCG) in a bulk nonlinear material (BNLM) with a positive thermo-optic coefficient (dn/dT>0 K−1), comprising:
- coupling light, which is emitted by a fs pulse oscillator at a first wavelength, into the BNLM, thereby producing nonlinear focusing of the coupled fs pulses in the BNLM, wherein the fs oscillator operates at a full repetition rate;
- providing interaction between the BNLM and light at a second wavelength different from the first wavelength and absorbable by the BNLM, thereby forming a thermal lens in the BNLM,
- wherein the nonlinear focusing of the fs pulses and thermal lens cumulatively generate the fs supercontinuum at the full repetition rate of the fs oscillator.
An optical schematic for controlling femtosecond supercontinuum generation (fs SCG), comprising:
- a fs oscillator outputting light having a train of fs pulses at a full PRR, which ranges between 10 MHz to 10 GHz, at a first wavelength;
- and
- a bulk nonlinear material (BNLM) receiving the fs pulses with a pulse energy inducing local nonlinear focusing which is insufficient for reaching a threshold of the fs SCG,
- the BNLM having a positive thermo-optic coefficient (dn/dT>0 K−1) and configured to absorb light at a second wavelength, which is different from the first wavelength, the absorbed light inducing heat dissipation through a cross-section of the first wavelength which forms a thermal lens along a length of the BNLM, wherein the thermal lens increases the intensity of the nonlinear focused fs pulses at the first wavelength to the threshold of the fs SCG.
Dependencies are inferred from the claim text.