Methods and systems for laser welding transparent materials with an ultrashort pulsed laser
First Claim
1. A method for welding materials, comprising:
- focusing a beam of ultrashort laser pulses near an interface between said materials, at least one of said materials being transparent at a wavelength of said ultrashort pulses; and
producing said ultrashort laser pulses at a repetition rate in the range from 100 kHz to 100 MHz, and with one or more zones of fluence sufficient to induce localized melting of said materials at said interface without ablation of said materials, said ultrashort pulses providing a fluence of more than about 0.01 J/cm2 in said one or more zones, and intensity sufficient to cause non-linear absorption within said materials, wherein a pulse to pulse temporal spacing corresponding to said repetition rate in said range is sufficiently small to cause accumulation of heat in said materials so as to induce said localized melting at said interface.
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Abstract
Methods and systems for ultrashort pulse laser processing of optically transparent materials are disclosed. At least one embodiment includes a method for welding materials with ultrashort laser pulses to create a bond through localized heating, at least one material being transparent at a laser wavelength. The ultrashort pulse duration causes nonlinear absorption of the laser radiation, and the high repetition rate of the laser causes pulse-to-pulse accumulation of heat within the materials. The laser is focused near the interface of the materials, generating sufficiently high fluence at the region to be welded. This minimizes damage to the rest of the material and enables fine weld lines. In various implementations the laser is focused near the sub-surface interface between two materials, generating high fluence at the region proximate to the laser focus with minimal modification to the surrounding region, including areas above and below the laser beam waist.
103 Citations
16 Claims
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1. A method for welding materials, comprising:
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focusing a beam of ultrashort laser pulses near an interface between said materials, at least one of said materials being transparent at a wavelength of said ultrashort pulses; and producing said ultrashort laser pulses at a repetition rate in the range from 100 kHz to 100 MHz, and with one or more zones of fluence sufficient to induce localized melting of said materials at said interface without ablation of said materials, said ultrashort pulses providing a fluence of more than about 0.01 J/cm2 in said one or more zones, and intensity sufficient to cause non-linear absorption within said materials, wherein a pulse to pulse temporal spacing corresponding to said repetition rate in said range is sufficiently small to cause accumulation of heat in said materials so as to induce said localized melting at said interface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for selectively creating a raised ridge at the interface between two opposed surfaces of two respective pieces to be welded to fill a gap, at least one of said pieces comprising transparent material, said method comprising:
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generating ultrashort pulses at a repetition rate in the range from 100 kHz to 100 MHz; focusing said ultrashort laser pulses within one or both of the two pieces, to selectively raise a ridge on one or both of said opposed surfaces; and subsequently laser welding a raised ridge to the opposed surface, or to a ridge selectively raised on the opposed surface. - View Dependent Claims (13)
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14. An optical system for welding materials, comprising:
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a laser system that produces a beam of ultrashort laser pulses having pulse widths in the range from about 50 fs to 500 ps and having a pulse repetition rate in the range from 100 kHz to 100 MHz; and a focusing element for focusing said beam near an interface between said materials, wherein said beam, at said interface, has a fluence of more than about 0.01 J/cm2, and an intensity insufficient to ablate said materials, wherein said laser system has a pulse repetition rate in said range high enough to cumulatively induce localized melting of said materials at said interface, and at least one of said materials is transparent to a wavelength of said ultrashort pulses. - View Dependent Claims (15, 16)
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Specification