Laser pulse selection and energy level control
Systems and methods are disclosed for selectively passing or blocking laser electromagnetic energy. A laser system comprises a shutter, whereby when the shutter is rotated one or more open areas of the shutter and one or more solid areas of the shutter are alternately positioned in a path of electromagnetic radiation emitted by the laser. The shutter may operate in different modes, including allowing all laser pulses to pass through in whole or in part, blocking all laser pulses from passing through, and alternately allowing and blocking laser pulses. In some embodiments, the shutter is controlled to allow only a part of each selected laser pulse to pass through. A laser system comprises a waveplate rotatable into different positions corresponding to different operating modes. The different operating modes may include allowing part and blocking part of the laser electromagnetic radiation.
1 . A laser system comprising:
a laser configured to emit electromagnetic radiation; and
a laser shutter assembly, wherein the laser shutter assembly comprises:
a shutter, the shutter having an axis of rotation and at least one open area and at least one solid area arranged around the axis of rotation of the shutter; and
a shutter rotation motor configured to rotate the shutter around the axis of rotation of the shutter,
wherein the shutter is arranged such that, when rotated around the axis of rotation of the shutter, an open area of the shutter and a solid area of the shutter are alternately positioned in a path of the electromagnetic radiation emitted by the laser,
wherein the shutter comprises a plurality of tracks corresponding to its different positions, including a first track in which a first percentage of laser pulses emitted by the laser are allowed to pass through and a second track in which a second percentage of laser pulses emitted by the laser are allowed to pass through, wherein the second percentage is higher than the first percentage.
2 . The laser system as recited in claim 1 , wherein the laser is configured to emit electromagnetic radiation in pulses, and wherein the laser shutter assembly is configured to operate in different modes, including an allow-all-pulses mode in which all laser pulses are allowed to pass through in whole or in part, a block-all-pulses mode in which the shutter blocks all laser pulses from passing through, and at least one intermittently-block-pulses mode in which some laser pulses are allowed to pass through in whole or in part and some laser pulses are blocked by the shutter.
3 . The laser system as recited in claim 2 , wherein the laser shutter assembly further comprises a shutter rotation sensor, and wherein the laser system is configured to operate the shutter rotation motor in response to signals from the shutter rotation sensor to control the rotation of the shutter with respect to the timing of the laser pulses.
4 . The laser system as recited in claim 2 , wherein the laser shutter assembly comprises a carriage position motor operatively connected to the shutter and configured to move the shutter into different positions corresponding to the different operating modes of the laser shutter assembly.
5 . The laser system as recited in claim 4 , wherein the laser shutter assembly further comprises a carriage cam plate and at least one carriage position sensor, wherein the carriage cam plate is connected to the shutter to move with the shutter, and wherein the at least one carriage position sensor is configured to detect a position of the carriage cam plate to determine a position of the shutter.
6 . The laser system as recited in claim 2 , wherein the laser system is configured to operate the shutter rotation motor to control the rotation of the shutter with respect to the timing of the laser pulses in order to operate the laser shutter assembly in its different modes.
7 . The laser system as recited in claim 2 , wherein the laser system is configured to operate the shutter rotation motor to control the rotation of the shutter with respect to the laser pulses such that, for at least a set of laser pulses, a part of each of the laser pulses in the set of laser pulses is allowed to pass and a part of each of the laser pulses in the set of laser pulses is blocked, in order to control laser energy output.
8 . A method of controlling a laser system comprising: emitting electromagnetic radiation from a laser; and
rotating a shutter in a path of the electromagnetic radiation emitted by the laser whereby an open area of the shutter and a solid area of the shutter are alternately positioned in the path of the electromagnetic radiation emitted by the laser,
wherein the shutter comprises a plurality of tracks corresponding to its different positions, including a first track in which a first percentage of laser pulses emitted by the laser are allowed to pass through and a second track in which a second percentage of laser pulses emitted by the laser are allowed to pass through, wherein the second percentage is higher than the first percentage.
9 . The method of controlling a laser system as recited in claim 8 , wherein the step of emitting electromagnetic radiation from the laser comprises emitting electromagnetic radiation from the laser in pulses, and further comprising operating the shutter in different modes, including an allow-all-pulses mode in which all laser pulses are allowed to pass through in whole or in part, a block-all-pulses mode in which the shutter blocks all laser pulses from passing through, and at least one intermittently-block-pulses mode in which some laser pulses are allowed to pass through in whole or in part and some laser pulses are blocked by the shutter.
10 . The method of controlling a laser system as recited in claim 9 , further comprising operating the shutter in response to signals from a shutter rotation sensor to control the rotation of the shutter with respect to the timing of the laser pulses.
11 . The method of controlling a laser system as recited in claim 9 , further comprising moving the shutter into different positions corresponding to the different operating modes using a carriage position motor operatively connected to the shutter.
12 . The method of controlling a laser system as recited in claim 11 , wherein the step of moving the shutter into different positions comprises moving the shutter into a first position in which the first percentage of the laser pulses emitted by the laser are allowed to pass through and into a second position in which the second percentage of the laser pulses emitted by the laser are allowed to pass through.
13 . The method of controlling a laser system as recited in claim 11 , further comprising determining a position of the shutter by detecting a position of a carriage cam plate using at least one carriage position sensor, wherein the carriage cam plate is connected to the shutter to move with the shutter.
14 . The method of controlling a laser system as recited in claim 9 , further comprising controlling the rotation of the shutter with respect to the timing of the laser pulses in order to operate the shutter in its different modes.
15 . The method of controlling a laser system as recited in claim 9 , further comprising controlling the rotation of the shutter with respect to the laser pulses such that, for at least a set of laser pulses, a part of each of the laser pulses in the set of laser pulses is allowed to pass and a part of each of the laser pulses in the set of laser pulses is blocked, in order to control laser energy output.