244 results about "Laser pulse width" patented technology

In one aspect the invention provides a method for laser induced breakdown of a material with a pulsed laser beam where the material is characterized by a relationship of fluence breakdown threshold (Fth) versus laser beam pulse width (T) that exhibits an abrupt, rapid, and distinct change or at least a clearly detectable and distinct change in slope at a predetermined laser pulse width value. The method comprises generating a beam of laser pulses in which each pulse has a pulse width equal to or less than the predetermined laser pulse width value. The beam is focused above the surface of a material where laser induced breakdown is desired. The region of least confusion (minimum beam waist or average spot size) is above the surface of the material in which laser induced breakdown is desired since the intensity of the beam falls off in the forward direction, preferably the region of the beam at or within the surface is between the region of least confusion and sufficient to remove material and the minimum intensity necessary for laser induced breakdown of the material to be removed, most preferably the region of minimum intensity is disposed at the surface of the material to be removed. The beam may be used in combination with a mask in the beam path. The beam or mask may be moved in the x, y, and Z directions to produce desired features. The technique can produce features smaller than the spot size and Rayleigh range due to enhanced damage threshold accuracy in the short pulse regime.

Systems and methods are provided for scribing wafers with short laser pulses so as to reduce the ablation threshold of target material. In a stack of material layers, a minimum laser ablation threshold based on laser pulse width is determined for each of the layers. The highest of the minimum laser ablation thresholds is selected and a beam of one or more laser pulses is generated having a fluence in a range between the selected laser ablation threshold and approximately ten times the selected laser ablation threshold. In one embodiment, a laser pulse width in a range of approximately 0.1 picosecond to approximately 1000 picoseconds is used. In addition, or in other embodiments, a high pulse repetition frequency is selected to increase the scribing speed. In one embodiment, the pulse repetition frequency is in a range between approximately 100 kHz and approximately 100 MHz.

A gated camera imaging system and method, utilizing a laser device for generating a beam of long duration laser pulses toward a target. A camera receives the energy of light reflexes of the pulses reflected from the target. The camera gating is synchronized to be set OFF for at least the duration of time it takes the laser device to produce a laser pulse in its substantial entirety, including an end of the laser pulse, in addition to the time it takes the laser pulse to complete traversing a zone proximate to the system and back to the camera, and set ON for an ON time duration thereafter until the laser pulse reflects back from the target and is received in the camera. The laser pulse width substantially corresponds to at least the ON time duration. Preferably, the laser device includes a Diode Laser Array (DLA).

The invention discloses a laser 3D printing method for a metal workpiece and a system thereof. The laser 3D printing method for the metal workpiece comprises the following steps that first, 3D sintering is conducted on metal powder through continuous laser or pulsed laser; second, laser-induced shock wave impact is conducted on the 3D sintered workpiece through short-pulse-width laser; and third, polishing treatment is conducted on the 3D sintered workpiece through continuous laser or pulsed laser. When the printed object contains different types of material powder, appropriate parameters such as the laser wave length, the pulse width and the pulse energy are chosen according to the optical characteristics of the material powder, and 3D printing of functionally-graded objects is realized through the three steps. Compared with the prior art, according to the laser 3D printing system, the laser sintering degree is controlled by changing the laser pulse width in the process of printing the metal workpiece, and the situations of porosity, over burning and spheroidization of the metal workpiece in the printing process are relieved, so that the compactness of the metal workpiece is improved.

Laser pulse energy adjustments are motivated by an understanding of the effect of laser pulse width variations among different lasers on satisfying a quality metric associated with a laser-processed target. In a preferred embodiment, the adjustments normalize this effect among different lasers drilling vias in a target specimen. The number of pulses delivered to the target specimen to form each via can be modified, based on the pulse energy applied to the via location, to control different via quality metrics.