Semiconductor elements for stabilizing laser output
First Claim
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1. A laser system that produces radiation at an operative wavelength, the system defining a laser cavity having an associated electric field pattern at the operative wavelength, and the system comprising:
- a mode-locking element configured to mode-lock output of the laser system; and
a nonlinear increasing loss element that includes a semiconductor material having a band-gap larger than the energy of a photon at the operative wavelength and smaller than twice the energy of a photon at the operative wavelength, and having a position with respect to the electric field pattern and a thickness such that the semiconductor material provides increasing absorption of radiation at the operative wavelength as energy density of radiation within the semiconductor material increases, to enhance stability of the mode-locked output.
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Abstract
Systems and methods for enhancing the stability of a mode-locked laser'"'"'s output are disclosed. The laser systems include a mode-locking element that mode-locks the laser'"'"'s output, and a semiconductor element. The semiconductor element produces a loss at the laser'"'"'s operative wavelength that increases as pulse energy increases, thereby enhancing the stability of the mode-locked output. The semiconductor elements can be used to enhance stability of both passively and actively mode-locked laser systems.
26 Citations
35 Claims
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1. A laser system that produces radiation at an operative wavelength, the system defining a laser cavity having an associated electric field pattern at the operative wavelength, and the system comprising:
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a mode-locking element configured to mode-lock output of the laser system; and
a nonlinear increasing loss element that includes a semiconductor material having a band-gap larger than the energy of a photon at the operative wavelength and smaller than twice the energy of a photon at the operative wavelength, and having a position with respect to the electric field pattern and a thickness such that the semiconductor material provides increasing absorption of radiation at the operative wavelength as energy density of radiation within the semiconductor material increases, to enhance stability of the mode-locked output. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A laser system that defines a laser cavity having an associated electric field pattern at an operative wavelength, the system comprising:
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a pump;
a gain medium that produces radiation at the operative wavelength when pumped by the pump;
a reflector disposed along an optical path in the cavity, the reflector comprising one or more layers of a first semiconductor material that acts as a saturable absorber at the operative wavelength to mode-lock output of the laser system, and one or more layers of a second semiconductor material having a band-gap larger than the energy of a photon at the operative wavelength and smaller than twice the energy of a photon at the operative wavelength, and having a position with respect to the electric field pattern and a thickness such that the second semiconductor material provides increasing absorption of radiation at the operative wavelength as energy density of radiation within the second semiconductor material increases, to enhance stability of the mode-locked output. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A laser system that defines a laser cavity having an associated electric field pattern at an operative wavelength, the system comprising:
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a pump;
a gain medium that produces radiation at the operative wavelength when pumped by the pump;
an element that actively mode-locks output of the laser system;
a structure disposed along an optical path in the cavity, the structure comprising a semiconductor material having a band-gap larder than the energy of a photon at the operative wavelength and smaller than twice the energy of a photon at the operative wavelength, and having a position with respect to the electric field pattern and a thickness such that the semiconductor material provides increasing absorption of radiation at the operative wavelength as energy density of radiation within the semiconductor material increases, to enhance stability of the mode-locked output. - View Dependent Claims (21, 22, 23, 24, 25)
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26. A method of enhancing the stability of a continuous wave mode-locked output of a laser, the laser producing radiation at an operative wavelength and the laser defining a cavity having an associated electric field pattern at the operative wavelength, the method comprising:
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passively mode-locking the output of the laser to produce a continuous train of pulses; and
stabilizing the continuous train of pulses against intensity fluctuations by incorporating into the cavity a nonlinear increasing loss element that includes a semiconductor material having a band-gap larger than the energy of a photon at the operative wavelength and smaller than twice the energy of a photon at the operative wavelength and having a position with respect to the electric field pattern and a thickness such that the semiconductor material provides increasing absorption of radiation at the operative wavelength as energy density of radiation within the semiconductor material increases, to enhance stability of the mode-locked output. - View Dependent Claims (27, 28, 29, 30, 31)
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32. A method of suppressing supermodes in the output of an actively mode-locked laser, the laser producing radiation at an operative wavelength and the laser defining a cavity having an associated electric field pattern at the operative wavelength, the method comprising:
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actively mode-locking the laser to produce a continuous train of pulses; and
incorporating a nonlinear increasing loss element into the cavity, the nonlinear increasing loss element including a semiconductor material having a band-gap larger than the energy of a photon at the operative wavelength and smaller than twice the energy of a photon at the operative wavelength, and having a position with respect to the electric field pattern and a thickness such that the semiconductor material provides increasing absorption of radiation at the operative wavelength as energy density of radiation within the semiconductor material increases, to limit peak intensity of the pulses, and thereby suppress supermodes. - View Dependent Claims (33, 34, 35)
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Specification