LASER BEAM ENERGY STABILIZING APPARATUS, PULSE TEMPORAL WAVEFORM CONTROL APPARATUS, LASER BEAM ENERGY STABILIZING METHOD, AND PULSE TEMPORAL WAVEFORM CONTROL METHOD
The present invention provides a laser beam control apparatus including: beam optical systems 33 and 34 for dividing a laser beam into a principal beam P and an auxiliary beam S and then for crossing the principal beam P and the auxiliary beam S; polarizing devices 36 and 37 for converting the laser beam before the division process into a linearly-polarized beam or converting the laser beams after the division process into linearly-polarized beams; a polarization direction change element 38 for changing the polarization direction of either one or both of the principal beam P and the auxiliary beam S; an optical gate element 35 provided at the intersection of the principal beam P and the auxiliary beam S and made of a material that exhibits the optical Kerr effect; and a polarization filter 39 for taking out from the principal beam P which has passed through the optical gate element 35 only a beam polarized in a predetermined direction.
1 . A laser beam energy stabilizing apparatus, comprising:
a) a beam optical system for dividing a linearly-polarized incident laser beam into a principal beam and an auxiliary beam and then for crossing the principal beam and the auxiliary beam;
b) a polarization direction change element for changing a polarization direction of either one or both of the principal beam and the auxiliary beam;
c) an optical gate element provided at an intersection of the principal beam and the auxiliary beam and made of a material that exhibits an optical Kerr effect; and
d) a polarization filter for taking out from the principal beam which has passed through the optical gate element only a beam polarized in a predetermined direction.
2 . A laser beam energy stabilizing apparatus, comprising:
a) an incident beam convertor for converting an incident laser beam into a linearly-polarized beam;
b) a beam optical system for dividing the incident laser beam which has been converted into a linearly-polarized beam into a principal beam and an auxiliary beam and then for crossing the principal beam and the auxiliary beam;
c) a polarization direction change element for changing a polarization direction of either one or both of the principal beam and the auxiliary beam;
d) an optical gate element provided at an intersection of the principal beam and the auxiliary beam and made of a material that exhibits an optical Kerr effect; and
e) a polarization filter for taking out from the principal beam which has passed through the optical gate element only a beam polarized in a predetermined direction.
3 . A laser beam energy stabilizing apparatus, comprising:
a) a beam optical system for dividing an incident laser beam into a principal beam and an auxiliary beam and then for crossing the principal beam and the auxiliary beam;
b) a linear polarizer for converting the principal beam and the auxiliary beam into beams linearly polarized in a same direction;
c) a polarization direction change element for changing a polarization direction of either one or both of the principal beam and the auxiliary beam;
d) an optical gate element provided at an intersection of the principal beam and the auxiliary beam and made of a material that exhibits an optical Kerr effect; and
e) a polarization filter for taking out from the principal beam which has passed through the optical gate element only a beam polarized in a predetermined direction.
4 . A laser beam energy stabilizing apparatus, comprising:
a) a beam optical system for dividing an incident laser beam into a principal beam and an auxiliary beam and then for crossing the principal beam and the auxiliary beam;
b) a polarization direction complex change element for converting both the principal beam and the auxiliary beam into a linearly-polarized beam so that their polarization directions differ by a predetermined angle;
c) an optical gate element provided at an intersection of the principal beam and the auxiliary beam and made of a material that exhibits an optical Kerr effect; and
d) a polarization filter for taking out from the principal beam which has passed through the optical gate element only a beam polarized in a predetermined direction.
5 . The laser beam energy stabilizing apparatus according to claim 1 , wherein:
in the beam optical system, from a point where the incident laser beam is divided into the principal beam and the auxiliary beam to a point where the principal beam and the auxiliary beam cross, an optical path length of the principal beam and that of the auxiliary beam are a same.
6 . The laser beam energy stabilizing apparatus according to claim 1 , wherein:
the predetermined direction is a same direction of the polarization of the principal beam before passing through the optical gate element.
7 . The laser beam energy stabilizing apparatus according to claim 1 , wherein:
the polarization direction change element makes an angle between the polarization directions of the principal beam and the auxiliary beam be 45 degrees.
8 . The laser beam energy stabilizing apparatus according to claim 4 , wherein:
in the beam optical system, from a point where the incident laser beam is divided into the principal beam and the auxiliary beam to a point where the principal beam and the auxiliary beam cross, an optical path length of the principal beam and that of the auxiliary beam are a same.
9 . The laser beam energy stabilizing apparatus according to claim 4 , wherein:
the predetermined direction is a same direction of the polarization of the principal beam before passing through the optical gate element.
10 . The laser beam energy stabilizing apparatus according to claim 4 , wherein:
the polarization direction change element makes an angle between the polarization directions of the principal beam and the auxiliary beam be 45 degrees.
11 . The laser beam energy stabilizing apparatus according to claim 1 , wherein:
the beam optical system injects the principal beam and the auxiliary beam which are perpendicular to each other into the optical gate element.
12 . The laser beam energy stabilizing apparatus according to claim 1 , wherein:
the beam optical system divides the incident laser beam into a principal beam and two auxiliary beams, and then crosses the principal beam and the two auxiliary beams at one point; and the laser beam control apparatus further comprises:
f) a principal beam incident angle setting unit for setting an incident angle of the principal beam entering into the optical gate element.
13 . The laser beam energy stabilizing apparatus according to claim 1 , wherein the optical gate element is made of any one of carbon disulfide, strontium titanate, dense flint glass, and bismuth glass.
14 . A pulse temporal waveform control apparatus for controlling a temporal waveform of laser pulses by using the laser beam energy stabilizing apparatus according to claim 1 .
15 . A laser beam energy stabilizing method, comprising the steps of:
a) dividing a linearly-polarized incident laser beam into a principal beam and an auxiliary beam;
b) changing a polarization direction of either one or both of the principal beam and the auxiliary beam;
c) crossing the principal beam and the auxiliary beam in an optical gate element made of a material that exhibits an optical Kerr effect; and
d) taking out from the principal beam which has passed through the optical gate element only a beam polarized in a predetermined direction.
16 . A laser beam energy stabilizing method, comprising the steps of:
a) converting an incident laser beam into a linearly-polarized beam;
b) dividing the incident laser beam which has been converted into a linearly-polarized beam into a principal beam and an auxiliary beam;
c) changing a polarization direction of either one or both of the principal beam and the auxiliary beam;
d) crossing the principal beam and the auxiliary beam in an optical gate element made of a material that exhibits an optical Kerr effect; and
e) taking out from the principal beam which has passed through the optical gate element only a beam polarized in a predetermined direction.
17 . A laser beam energy stabilizing method, comprising the steps of:
a) converting an incident laser beam into a principal beam and an auxiliary beam;
b) converting the principal beam and the auxiliary beam into a beam linearly-polarized in a same direction;
c) changing a polarization direction of either one or both of the principal beam and the auxiliary beam;
d) crossing the principal beam and the auxiliary beam in an optical gate element made of a material that exhibits an optical Kerr effect; and
e) taking out from the principal beam which has passed through the optical gate element only a beam polarized in a predetermined direction.
18 . A laser beam energy stabilizing method, comprising the steps of:
a) dividing an incident laser beam into a principal beam and an auxiliary beam;
b) converting both the principal beam and the auxiliary beam into a linearly-polarized beam so that their polarization directions differ by a predetermined angle;
c) crossing the principal beam and the auxiliary beam in an optical gate element made of a material that exhibits an optical Kerr effect;
d) taking out from the principal beam which has passed through the optical gate element only a beam polarized in a predetermined direction.
19 . The laser beam energy stabilizing method according to claim 15 , wherein:
from a point where the incident laser beam is divided into the principal beam and the auxiliary beam to a point where the principal beam and the auxiliary beam cross, an optical path length of the principal beam and that of the auxiliary beam are a same.
20 . The laser beam energy stabilizing method according to claim 15 , wherein:
the predetermined direction is a same direction of the polarization of the principal beam before passing through the optical gate element.
21 . The laser beam energy stabilizing method according to claim 15 , wherein:
an angle between the polarization directions of the principal beam and the auxiliary beam is 45 degrees.
22 . A pulse temporal waveform control method for controlling a temporal waveform of laser pulses by using the laser beam energy stabilizing method according to claim 15 .