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US 7,253,933 B1Granted
Apparatus and method for the temporal profiling of short laser pulses with thick Bragg gratings
AssigneeHRL Laboratories, LLC
InventorOleg M. Efimov
Life of this patent
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Abstract
A system and/or method for temporal profiling of an incident laser pulse. The system and/or method includes a laser beam source for providing the incident laser pulse and a Bragg grating (BG) coupled to receive the incident laser pulse. The BG includes a distribution of diffraction efficiency density at various depths within the BG and provides a plurality of diffracted beamlets from the incident laser pulse. The system and/or method combines the diffracted beamlets into a single temporally shaped laser beam.
Claims23
A method for temporal beam profiling of an incident laser pulse from a source, the method comprising:
- providing a Bragg grating (BG);
- directing the incident laser pulse into the BG;
- diffracting the incident laser pulse at various depths within the BG into a plurality of diffracted beamlets having a plurality of amplitudes and time delays;
- and
- combining the diffracted beamlets into a single temporally shaped laser beam,
- wherein the various depths within the BG have a distribution of a refractive index modulation to provide a distribution of a diffraction efficiency density.
3 more elements
A method for temporal beam profiling of an incident laser pulse from a source, the method comprising:
- providing a Bragg grating (BG);
- directing the incident laser pulse into the BG;
- diffracting the incident laser pulse at various depths within the BG into a plurality of diffracted beamlets having a plurality of amplitudes and time delays;
- and
- combining the diffracted beamlets into a single temporally shaped laser beam,
- wherein the various depths within the BG have a distribution of a diffraction efficiency density;
- wherein a delay, Δt, of the plurality of time delays of a diffracted beamlet of the plurality of diffracted beamlets diffracted at a depth, l, of the BG is determined by:
- Δ
-
-
- t
- =
- l
- L
- ·
- L
-
- (
- n
- +
- cos
-
-
- α
- )
- c
- wherein, n, is an average refractive index of the BG, α, is the angle between the incident laser pulse and the diffracted beamlet, c, is the light speed in the vacuum, and, L, is a total length of the BG.
24 more elements
A method for temporal beam profiling of an incident laser pulse from a source, the method comprising:
- providing a Bragg grating (BG);
- directing the incident laser pulse into the BG;
- diffracting the incident laser pulse at various depths within the BG into a plurality of diffracted beamlets having a plurality of amplitudes and time delays;
- and
- combining the diffracted beamlets into a single temporally shaped laser beam,
- wherein the various depths within the BG have a distribution of a diffraction efficiency density;
- wherein a maximum time delay, T, of the plurality of time delays of a diffracted beamlet of the plurality of diffracted beamlets is determined by:
- T
- =
- L
-
- (
- n
- +
- cos
-
-
- α
- )
- c
- wherein, n, is an average refractive index of the BG, α, is the angle between the incident laser pulse and the diffracted beamlet, c, is the light speed in the vacuum, and, L, is a total length of the BG.
18 more elements
A method for temporal beam profiling of an incident laser pulse from a source, the method comprising:
- providing a Bragg grating (BG);
- directing the incident laser pulse into the BG;
- diffracting the incident laser pulse at various depths within the BG into a plurality of diffracted beamlets having a plurality of amplitudes and time delays;
- and
- combining the diffracted beamlets into a single temporally shaped laser beam,
- wherein the various depths within the BG have a distribution of a diffraction efficiency density;
- wherein the diffracting the incident laser pulse at the various depths within the BG comprises fragmenting the incident laser pulse at the various depths within the BG into a plurality of diffracted pulses;
- wherein the incident pulse comprises a plurality of pulse wavelengths and wherein each of the plurality of diffracted pulses corresponds to one of the specified pulse wavelengths, intensities, and temporal shapes.
5 more elements
A system for temporal shaping of an incident laser pulse from a laser beam source, the system comprising:
- a Bragg grating (BG) coupled to receive the incident laser pulse from the laser beam source, the BG having a height that is less than the physical length of the incident laser pulse and producing a plurality of diffracted beamlets;
- and
- a fiber coupled to receive the diffracted beamlets and to combine the diffracted beamlets into a single temporally shaped laser beam from the incident laser pulse,
- wherein the BG has a distribution of a refractive index modulation to fragments the incident laser beam at various depths within the BG into the plurality of diffracted beamlets,
- wherein each of the plurality of diffracted beamlets has a corresponding beam amplitude and delay, and
- wherein the combination of the various beam amplitudes and delays of the diffracted beamlets provides the temporal shaped laser beam.
3 more elements
A system for temporal shaping of an incident laser pulse from a laser beam source, the system comprising:
- a Bragg grating (BG) coupled to receive the incident laser pulse from the laser beam source, the BG having a height that is less than the physical length of the incident laser pulse and producing a plurality of diffracted beamlets;
- and
- a fiber coupled to receive the diffracted beamlets and to combine the diffracted beamlets into a single temporally shaped laser beam from the incident laser pulse,
- wherein the BG fragments the incident laser beam at various depths within the BG into the plurality of diffracted beamlets,
- wherein each of the plurality of diffracted beamlets has a corresponding beam amplitude and delay, and
- wherein the combination of the various beam amplitudes and delays of the diffracted beamlets provides the temporal shaped laser beam;
- wherein the various depths within the BG comprise a distribution of a diffraction efficiency density;
- wherein the distribution of the diffraction efficiency density, H(x), is determined by:
- H
-
- (
- x
- )
- =
- f
-
- (
- x
- )
- ∫
- 0
- 1
-
- f
-
- (
- x
- ′
- )
-
-
- ⅆ
- x
- ′
- -
- ∫
- 0
- x
-
- f
-
- (
- x
- ′
- )
-
-
- ⅆ
- x
- ′
- ,
- wherein f(x) is a functional dependence of the specified intensity distribution along a non-dimensional thickness, x=1/L, of the BG, and
- wherein l is the local depth and L is the total thickness of the BG.
50 more elements
A system for temporal beam shaping of an incident laser pulse from a laser beam source, the system comprising:
- means for directing the incident laser pulse into a Bragg grating (BG) having a height that is less than a physical length of the incident laser pulse;
- and
- means for fragmenting the incident laser pulse at various depths within the BG into a plurality of diffracted beamlets, wherein the various depths within the BG have a distribution of a refractive index modulation to provide a distribution of a diffraction efficiency density for temporally shaping the incident laser pulse into the plurality of diffracted beamlets;
- means for providing a corresponding intensity and delay to each of the plurality of diffracted beamlets;
- wherein a combination of the various diffracted beamlets provides a temporally shaped laser beam.
2 more elements
Dependencies are inferred from the claim text.