A calculating section of a control unit calculates a vertical position Defocus for a condensing lens using a height value H1 of a modified layer in a wafer that is set by a setting section according to the equation (1) below.
Defocus=(thickness T1 of wafer−height value H1−b)/a  (1) The calculating section calculates an appropriate vertical position for the condensing lens according to the equation (1) depending on the height value H1 of the modified layer that is set by the setting section. Therefore, the vertical position of the condensing lens in laser processing operation can be determined more easily, and a time-consuming and tedious experiment for fine adjustment of the vertical position of the condensing lens does not need to be conducted.

A calculating section of a control unit calculates a vertical position Defocus for a condensing lens using a height value H1 of a modified layer in a wafer that is set by a setting section according to the equation (1) below.
Defocus=(thickness T1 of wafer−height value H1−b)/a  (1) The calculating section calculates an appropriate vertical position for the condensing lens according to the equation (1) depending on the height value H1 of the modified layer that is set by the setting section. Therefore, the vertical position of the condensing lens in laser processing operation can be determined more easily, and a time-consuming and tedious experiment for fine adjustment of the vertical position of the condensing lens does not need to be conducted.

Disclosed is a method for marking an optical article coated with an interference coating including at least two layers, an inner layer and an outer layer, and having reflection coefficient Re; by exposure of the inner layer, at a marking point, by way of a laser beam at a marking wavelength, in such a way as to ablate the inner layer and any layer further away from the substrate; the ablated area having a reflection coefficient Rm different from Re by at least 1%; the inner layer absorbing the marking wavelength to a greater degree than any layer further away from the substrate. Also disclosed is an optical article coated with an interference coating having at least two layers, an inner layer and an outer layer, the article including a marking pattern formed by local absence of layers.

Disclosed is a method for marking an optical article coated with an interference coating including at least two layers, an inner layer and an outer layer, and having reflection coefficient Re; by exposure of the inner layer, at a marking point, by way of a laser beam at a marking wavelength, in such a way as to ablate the inner layer and any layer further away from the substrate; the ablated area having a reflection coefficient Rm different from Re by at least 1%; the inner layer absorbing the marking wavelength to a greater degree than any layer further away from the substrate. Also disclosed is an optical article coated with an interference coating having at least two layers, an inner layer and an outer layer, the article including a marking pattern formed by local absence of layers.

A device for fabricating a quartz microfluidic chip by a femtosecond pulse cluster. The device includes: a femtosecond pulse cluster laser source configured to output a femtosecond pulse cluster; a beam splitting and interference system, configured to split the femtosecond pulse cluster into a plurality of parts, and to converge split parts to form a femtosecond pulse cluster plasma or a femtosecond pulse cluster plasma grating; a sample system configured to move the electronic displacement platform where a quartz glass is placed to control a position where the parts of the femtosecond pulse cluster are converged on the quartz glass; and a hydrofluoric acid immersion system configured to immerse the quartz glass in a diluent hydrofluoric acid solution to remove an ablated part of the quartz glass to form the quartz microfluidic chip.

A colored sapphire material and methods for coloring sapphire material using lasers are disclosed. The method for coloring the sapphire material may include positioning the sapphire material over an opaque substrate material, exposing the opaque substrate material to a laser beam passing through the sapphire material to impact the substrate material, and inducing a chemical change in a portion of the sapphire material exposed to the laser beam. The method may also include creating a visible color in the portion of the sapphire material as a result of the chemical change. The colored sapphire material may include a first transparent portion, and a second, colored portion substantially surrounded by the first portion. The second, colored portion may have a chemical composition different than that of the first portion.

A colored sapphire material and methods for coloring sapphire material using lasers are disclosed. The method for coloring the sapphire material may include positioning the sapphire material over an opaque substrate material, exposing the opaque substrate material to a laser beam passing through the sapphire material to impact the substrate material, and inducing a chemical change in a portion of the sapphire material exposed to the laser beam. The method may also include creating a visible color in the portion of the sapphire material as a result of the chemical change. The colored sapphire material may include a first transparent portion, and a second, colored portion substantially surrounded by the first portion. The second, colored portion may have a chemical composition different than that of the first portion.

A wafer processing method includes a modified layer forming step of applying a laser beam of a wavelength having transmitting property to a wafer with a focusing point of the laser beam positioned inside the wafer at positions corresponding to division lines, thereby to form modified layers, and a back side grinding step of holding the wafer on a chuck table of a grinding apparatus, grinding a back side of the wafer to thin the wafer, and dividing the wafer into individual device chips from cracks that are generated from the modified layers formed inside the wafer along the division lines to the division lines formed on a front side of the wafer. In the modified layer forming step, in a case where triangular chips each having a surface area smaller than the device chips are to be formed, the application of the laser beam is stopped in a region where the triangular chips are to be formed.

A wafer processing method includes a modified layer forming step of applying a laser beam of a wavelength having transmitting property to a wafer with a focusing point of the laser beam positioned inside the wafer at positions corresponding to division lines, thereby to form modified layers, and a back side grinding step of holding the wafer on a chuck table of a grinding apparatus, grinding a back side of the wafer to thin the wafer, and dividing the wafer into individual device chips from cracks that are generated from the modified layers formed inside the wafer along the division lines to the division lines formed on a front side of the wafer. In the modified layer forming step, in a case where triangular chips each having a surface area smaller than the device chips are to be formed, the application of the laser beam is stopped in a region where the triangular chips are to be formed.

A grinding apparatus conveys a wafer from a first rough grinding unit and a first finish grinding unit to a first laser beam irradiation unit by a turntable. Thus, in one grinding apparatus, the wafer can be ground and damage of the wafer caused due to the grinding can be repaired easily and rapidly. Therefore, it is possible to execute the grinding of the wafer and the repair of the damage efficiently and favorably.