Apparatus and method for mode selection in a photonic band edge laser
AssigneeChiral Photonics, Inc.
InventorsVictor Il'ich Kopp, Azriel Zelig Genack
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Abstract
The present invention advantageously enables single-mode lasing at higher pump power and further enables general reduction of the lasing radiation bandwidth. This is accomplished by producing an appropriate spatial gain distribution inside the laser medium. The present invention further enables advantageous selection of a particular photonic mode for lasing at that mode in a periodic laser by varying spatial gain distribution within the periodic laser medium. Photonic mode selection by varying gain distribution within the laser medium is accomplished in accordance with various embodiments of the present invention.
Claims53
A laser apparatus comprising:
- a periodic structure configured to produce a photonic stop band having a high frequency band edge comprising a first plurality of high frequency photonic modes of sequentially increasing frequencies and a low frequency band edge comprising a corresponding second plurality of low frequency photonic modes of sequentially decreasing frequencies, said periodic structure being doped with a uniformly distributed gain medium;
- and
- excitation means, applied to said periodic structure at a first excitation frequency corresponding to a selected one of said plural high frequency photonic modes, for causing said gain medium to emit electromagnetic radiation at a corresponding low frequency mode of said second plurality of low frequency photonic modes, such that lasing at a lasing wavelength corresponding to said low frequency mode occurs in a direction perpendicular to said periodic structure.
A laser apparatus comprising:
- a periodic structure configured to produce a photonic stop band having a high frequency band edge comprising a high frequency first photonic mode and a low frequency band edge comprising a low frequency first photonic mode, said periodic structure being doped with a uniformly distributed gain medium;
- an optical excitation means, for producing a gaussian light beam directed at said periodic structure;
- and
- focusing means for focusing said light beam at a substantially central portion of said periodic structure to excite said gain medium causing peak gain at said substantially central portion of said periodic structure so that said gain medium emits electromagnetic radiation such that lasing at a lasing wavelength corresponding to one of said low frequency first photonic mode and said high frequency first photonic mode occurs in a direction perpendicular to said periodic structure.
A laser apparatus comprising:
- a periodic structure configured to produce a photonic stop band having a high frequency band edge comprising a first plurality of high frequency photonic modes of sequentially increasing frequencies and a low frequency band edge comprising a corresponding second plurality of low frequency photonic modes of sequentially decreasing frequencies, said periodic structure being doped with a gain medium distributed within said periodic structure in a plurality of equally spaced alternating regions of high and low gain medium concentration;
- and
- an excitation means, applied to said periodic structure, for causing said gain medium to emit electromagnetic radiation at a particular frequency mode, a number of said particular frequency mode corresponding to a number of high gain medium concentration regions within said periodic structure, such that lasing at a lasing wavelength corresponding to said particular frequency mode occurs in a direction perpendicular to said periodic structure.
A laser apparatus comprising:
- a conductive periodic structure configured to produce a photonic stop band having a high frequency band edge comprising a first plurality of high frequency photonic modes of sequentially increasing frequencies and a low frequency band edge comprising a corresponding second plurality of low frequency photonic modes of sequentially decreasing frequencies, said periodic structure being doped with a uniformly distributed electrically excitable gain medium;
- and
- a excitation means for applying a spatially non-uniform electrical current to said periodic structure to produce a plurality of alternating high gain and low gain regions within said periodic structure and to cause, said gain medium to emit electromagnetic radiation at a particular frequency mode, a number of said particular frequency mode corresponding to a number of high gain regions within said periodic structure, such that lasing at a lasing wavelength corresponding to said particular frequency mode occurs in a direction perpendicular to said periodic structure.
A laser apparatus comprising:
- a periodic structure configured to produce a photonic stop band having a high frequency band edge comprising a first plurality of high frequency photonic modes of sequentially increasing frequencies and a low frequency band edge comprising a corresponding second plurality of low frequency photonic modes of sequentially decreasing frequencies, said periodic structure being doped with a uniformly distributed gain medium and being configured as a vertical cavity liquid crystal laser;
- and
- a excitation means for applying a spatially and intensity non-uniform optical excitation to said periodic structure to produce a plurality of alternating high gain and low gain regions within said periodic structure and to cause said gain medium to emit electromagnetic radiation at a particular frequency mode, a number of said particular frequency mode corresponding to a number of high gain regions within said periodic structure, such that lasing at a lasing wavelength corresponding to said particular frequency mode occurs in a direction perpendicular to said periodic structure.
A laser apparatus comprising:
- a periodic structure configured to produce a photonic stop band having a high frequency band edge comprising a first plurality of high frequency photonic modes of sequentially increasing frequencies and a low frequency band edge comprising a corresponding second plurality of low frequency photonic modes of sequentially decreasing frequencies, said periodic structure being doped with a gain medium;
- and
- mode selection means for selecting a mode from one of said first plurality of high frequency photonic modes and second plurality of low frequency photonic modes, comprising:
- means for varying gain distribution within said periodic structure to produce a non-uniform gain distribution having at least one gain peak therein, and
- excitation means, applied to said periodic structure, for causing said gain medium to emit electromagnetic radiation at a particular frequency mode, a number of said particular frequency mode corresponding to a number of gain peaks within said periodic structure, such that lasing at a lasing wavelength corresponding to said particular frequency mode occurs in a direction perpendicular to said periodic structure.
A method of lasing implemented in a periodic structure configured to produce a photonic stop band having a high frequency band edge comprising a first plurality of high frequency photonic modes of sequentially increasing frequencies and a low frequency band edge comprising a corresponding second plurality of low frequency photonic modes of sequentially decreasing frequencies, said periodic structure being doped with a uniformly distributed gain medium, the method comprising the step of:
- (a) applying excitation to said periodic structure at a first excitation frequency corresponding to a selected one of said plural high frequency photonic modes, thereby causing said gain medium to emit electromagnetic radiation at a corresponding low frequency mode of said second plurality of low frequency photonic modes, such that lasing at a lasing wavelength corresponding to said low frequency mode occurs in a direction perpendicular to said periodic structure.
A method of lasing implemented in a periodic structure configured to produce a photonic stop band having a high frequency band edge comprising a high frequency first photonic mode and a low frequency band edge comprising a low frequency first photonic mode, said periodic structure being doped with a uniformly distributed gain medium, comprising the steps of:
- (a) producing a gaussian light beam directed at the periodic structure;
- and
- (b) focusing said light beam at a substantially central portion of said periodic structure to excite said gain medium causing peak gain at said substantially central portion of said periodic structure so that said gain medium emits electromagnetic radiation such that lasing at a lasing wavelength corresponding to one of said low frequency first photonic mode and said high frequency first photonic mode occurs in a direction perpendicular to said periodic structure.
A method of lasing implemented in a periodic structure configured to produce a photonic stop band having a high frequency band edge comprising a first plurality of high frequency photonic modes of sequentially increasing frequencies and a low frequency band edge comprising a corresponding second plurality of low frequency photonic modes of sequentially decreasing frequencies, said periodic structure being doped with a gain medium distributed within said periodic structure in a plurality of equally spaced alternating regions of high and low gain medium concentration, the method comprising the step of:
- (a) applying excitation to said periodic structure to cause said gain medium to emit electromagnetic radiation at a particular frequency mode, a number of said particular frequency mode corresponding to a number of high gain medium concentration regions within said periodic structure, such that lasing at a lasing wavelength corresponding to said particular frequency mode occurs in a direction perpendicular to said periodic structure.
A method of lasing implemented in a conductive periodic structure configured to produce a photonic stop band having a high frequency band edge comprising a first plurality of high frequency photonic modes of sequentially increasing frequencies and a low frequency band edge comprising a corresponding second plurality of low frequency photonic modes of sequentially decreasing frequencies, said periodic structure being doped with a uniformly distributed electrically excitable gain medium, the method comprising the step of:
- (a) applying a spatially non-uniform electrical current to said periodic structure to produce a plurality of alternating high gain and low gain regions within said periodic structure and to cause said gain medium to emit electromagnetic radiation at a particular frequency mode, a number of said particular frequency mode corresponding to a number of high gain regions within said periodic structure, such that lasing at a lasing wavelength corresponding to said particular frequency mode occurs in a direction perpendicular to said periodic structure.
A method of lasing implemented in a periodic structure configured to produce a photonic stop band, having a high frequency band edge comprising a first plurality of high frequency photonic modes of sequentially increasing frequencies and a low frequency band edge comprising a corresponding second plurality of low frequency photonic modes of sequentially decreasing frequencies, said periodic structure being doped with a uniformly distributed gain medium and being configured as a vertical cavity liquid crystal laser, said method comprising the step of:
- (a) applying a spatially and intensity non-uniform optical excitation to said periodic structure to produce a plurality of alternating high gain and low gain regions within said periodic structure and to cause said gain medium to emit electromagnetic radiation at a particular frequency mode, a number of said particular frequency mode corresponding to a number of high gain regions within said periodic structure, such that lasing at a lasing wavelength corresponding to said particular frequency mode occurs in a direction perpendicular to said periodic structure.
A method of lasing implemented in a periodic structure configured to produce a photonic stop band having a high frequency band edge comprising a first plurality of high frequency photonic modes of sequentially increasing frequencies and a low frequency band edge comprising a corresponding second plurality of low frequency photonic modes of sequentially decreasing frequencies, said periodic structure being doped with a gain medium, the method comprising the steps of:
- (a) selecting a mode from one of said first plurality of high frequency photonic modes and second plurality of low frequency photonic modes by varying gain distribution within said periodic structure to produce a non-uniform gain distribution having at least one gain peak therein, and
- (b) applying excitation to said periodic structure, to cause said gain medium to emit electromagnetic radiation at a particular frequency mode, a number of said particular frequency mode corresponding to a number of gain peaks within said periodic structure, such that lasing at a lasing wavelength corresponding to said particular frequency mode occurs in a direction perpendicular to said periodic structure.
Dependencies are inferred from the claim text.