Method and device for laser micromachining

1. A laser micromachining device for drilling holes in a sample made of a given material, comprising:

a laser source configured to generate an incident beam comprising at least one light pulse; and

a spatial conditioning optical system having an optical axis and configured to generate and focus, from the incident beam, a non-diffracting beam of Bessel-Vortex type, the focused non-diffracting beam having a property of maintaining a constant profile along the optical axis, and having a shape of a hollow cylinder of given dimensions oriented along the optical axis, wherein the focused non-diffracting beam is a focusing cylinder

wherein the spatial conditioning optical system is configured to adapt a size and a position of the focused non-diffracting beam in the sample, and

wherein the laser source is designed to generate, after the focusing in the sample, a plasma of free charges by multi-photonic absorption in a volume of the sample situated on the lateral surface of said focusing cylinder, said plasma generates a hole formation.

2. The device as claimed in claim 1 , in which the at least one light pulse has a duration of less than 100 picoseconds.

3. The device as claimed in claim 1 , in which said laser source allows the emission of a first light pulse or of a train of first light pulses of given optical power, higher than a first optical power threshold, said first optical power threshold being sufficient for causing a modification of one or more physico-chemical properties of the material at the location of formation of the plasma.

4. The device as claimed in claim 3 , in which said optical power is higher than a second optical power threshold sufficient for causing an ablation of the material at the location of formation of the plasma.

5. The device as claimed in claim 1 , in which the laser source allows the emission of at least a second electromagnetic wave designed to be spatially superposed at the location of formation of the plasma.

6. The device as claimed in claim 5 , in which said laser source comprises a single laser source, and wherein a first and at least a second light pulse are conditioned in a time-domain to be generated starting from a light wave emitted by said laser source.

7. The device as claimed in claim 1 , in which the optical system allows a beam to be generated having an annular distribution of an intensity in a space of spatial frequencies and a phase in the space of the spatial frequencies of the type Φ(k r ,θ)=Nθ, where (k r ,θ) are the cylindrical coordinates and N is a relative non-zero integer.

8. The device as claimed in claim 1 , in which the optical system allows, after focusing in said sample, a plurality of focusing cylinders to be formed simultaneously.

9. The device as claimed in claim 1 , wherein the laser source is configured to condition a polarization of light pulses.

10. The device as claimed in claim 1 , wherein the focusing cylinder is configured to evacuate the material contained inside the focusing cylinder.

11. A method for drilling holes in a sample made of a material having a given transparency band by laser micromachining, comprising:

emitting an incident beam comprising at least one light pulse with a spectral band included within the transparency band of said material; and

spatial conditioning said first pulse for generating, after focusing in said sample, a non-diffracting beam of Bessel-Vortex type, the focused non-diffracting beam having a property of maintaining a constant profile along an optical axis, and having a shape of a hollow cylinder of given dimensions oriented along the optical axis, the focused non-diffracting beam being a focusing cylinder,

wherein light intensity of said non-diffracting beam allows a plasma of free charges to be generated by multi-photonic absorption within a volume of the sample situated on the lateral surface of said focusing cylinder, said plasma generates a hole formation.

12. The method as claimed in claim 11 , further comprising emitting a first light pulse or of a train of light pulses with an optical power sufficient to cause a modification of one or more physico-chemical properties of the material at the location of formation of the plasma.

13. The method as claimed in claim 12 , in which said optical power is sufficient for causing an ablation of the material at the location of formation of the plasma.

14. The method as claimed in claim 11 , further comprising:

emitting at least a second electromagnetic wave with a spectral band included within the transparency band of said material, spatially superposed at the location of formation of the plasma so as to generate a heating up of said material by absorption by the free charges of the plasma.

15. The method as claimed in claim 11 , applied to the micro-drilling of a sample made of a given material for the formation of at least one through-hole, comprising:

controlling the diameter of the through-hole by the control of the spatial conditioning parameters of the at least one light pulse; and

controlling the relative position of the sample and the focused non-diffracting beam.

16. The method as claimed in claim 15 , further comprising:

evacuating the material contained inside the focusing cylinder in order to form said through-hole.

17. The method as claimed in claim 11 applied to the cleaving of a sample, further comprising:

displacing the focused non-diffracting beam along a cleaving plane.