Device for maintaining alignment between a focal point of a laser beam and a slit aperture
AssigneeAgfa NV
InventorJohn Nolan
Life of this patent
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Abstract
An optical wedge compensates for a vertically drifting laser beam in response to ambient temperature fluctuations. A slit sensor is formed onto a surface of the wedge to separate a single light pulse from a plurality of light pulses. A reflective filter layer is applied to a side opposite the slit sensor so an incident laser beam is attenuated thereby precluding damage to the slit sensor. The reflective filter coating further filters out unwanted light energy. The wedge is shaped so as to maintain a position of a focal point of a laser beam on the slit sensor and to prevent reflected light from damaging a laser source.
Claims29
An optical wedge for shifting and maintaining a position of a focal point of an incident beam of light onto an aperture, said shift being proportional to a thickness of said optical wedge, said optical wedge comprising:
- a first planar side in the optical pathway of a beam of light, said first side positioned at a first angle relative to said beam of light;
- a reflective filter coating deposed on an outside surface of said first planar side between said beam of light and said optical wedge for attenuating said beam of light and for reflecting light having wavelengths other than said beam of light;
- a second planar side angularly positioned relative to said first planar side such that a second angle formed by said first side and said second side is less than 90 degrees thereof;
- an opaque coating deposed on an outside surface of said second side for blocking said beam of light;
- and
- an aperture formed into said opaque coating, said aperture operative to separate a single pulse of light from a plurality of light pulses.
An optical wedge for shifting a position of a focal point of an incident beam of light onto an aperture, said shift being proportional to a thickness of said optical wedge, said optical wedge comprising:
- a reflective filter layer in continuous and direct contact with a first outside surface of said optical wedge for attenuating a beam of light and for reflecting light having wavelengths other than said beam of light;
- an opaque layer in continuous and direct contact with a second outside surface of said optical wedge for blocking said beam of light;
- and
- an aperture formed into said opaque layer, said aperture operative to separate a single pulse of light from a plurality of light pulses.
A device for providing a variable optical path length operative to shift a focal point of an incident light beam onto an aperture in response to vertical movement of a moveable light source, said device comprising:
- a generally wedge shaped piece of optical glass;
- a reflective filter layer in continuous and direct contact with a first outside surface of said optical wedge for attenuating a beam of light and for reflecting light having wavelengths other than said beam of light;
- an opaque layer in continuous and direct contact with a second outside surface of said optical wedge for blocking said beam of light;
- and
- an aperture formed into said opaque layer, said aperture operative to separate a single pulse of light from a plurality of light pulses.
A device for providing a variable optical path length operative to shift a focal point of an incident light beam onto an aperture in response to vertical movement of a moveable light source, said device comprising:
- a generally wedge shaped piece of optical glass;
- a first planar side in the optical pathway of a beam of light, said first side positioned at a first angle relative to said beam of light;
- a reflective filter coating deposed on an outside surface of said first planar side between said beam of light and said optical wedge for attenuating said beam of light and for reflecting light having wavelengths other than said beam of light;
- a second planar side angularly positioned relative to said first planar side such that a second angle formed by said first side and said second side is less than 90 degrees thereof;
- an opaque coating deposed on an outside surface of said second side for blocking said beam of light;
- and
- an aperture formed into said opaque coating, said aperture operative to separate a single pulse of light from a plurality of light pulses.
A method of measuring an optical parameter of a pulsed laser beam comprising the steps of:
- providing an optical wedge comprising:
- a generally wedge shaped piece of optical glass;
- a reflective filter layer in continuous and direct contact with a first outside surface of said optical wedge for attenuating said laser beam and for reflecting light having wavelengths other than said laser beam;
- an opaque layer in continuous and direct contact with a second outside surface of said optical wedge for blocking said laser beam;
- and
- a slit-shaped aperture formed into said opaque layer, said aperture operative to separate a single pulse of light from a plurality of light pulses;
- positioning said optical wedge so that said first outside surface of said optical wedge is located in the optical pathway of said laser beam, said first side positioned at an angle that is non-orthogonal to said laser beam;
- and
- detecting light from said laser beam after said light passes through said optical wedge.
Dependencies are inferred from the claim text.