Abstract:
Prism-coupling systems and methods for characterizing large depth-of-layer waveguides are disclosed. The systems and methods utilize a coupling prism having a coupling angle α having a maximum coupling angle αmax at which total internal reflection occurs. The prism angle α is in the range 0.81αmax≦α≦0.99αmax. This configuration causes the more spaced-apart lower-order mode lines to move closer together and the more tightly spaced higher-order mode lines to separate. The adjusted mode-line spacing allows for proper sampling at the detector of the otherwise tightly spaced mode lines. The mode-line spacings of the detected mode spectra are then corrected via post-processing. The corrected mode spectra are then processed to obtain at least one characteristic of the waveguide.
Abstract:
Chemically strengthened glass articles having at least one deep compressive layer extending from a surface of the article to a depth of layer DOL of about 130 μm up to about 175 μm or, alternatively, to a depth of compression (DOC) in a range from about 90 μm to about 120 μm within the article. The compressive layer has a stress profile that includes a first substantially linear portion extending from a relatively shallow depth to the DOL or DOC and a second portion extending from the surface to the shallow depth. The second portion is substantially linear at a depth from 0 μm to 5 μm and has a steeper slope than that of the first portion of the profile. Methods of achieving such stress profiles are also described.
Abstract:
Apparatus and methods for measuring mode spectra for ion-exchanged glass substrates having a steep index region are disclosed. An interfacing fluid is provided between the coupling prism and the glass substrate. The interfacing fluid thickness is selected so that the variation in modal birefringence with fluid thickness is reduced to an acceptable level. The coupling prism can include a prism coating on the coupling surface so that the substrate-prism interface includes the prism coating. The coupling prism can also include stand-off members that serve to define the thickness of the interfacing fluid.
Abstract:
Systems and methods of for measuring birefringence and stress in a sample made of ion-exchanged glass or a ceramic are disclosed, wherein the method includes digitally capturing TE and TM angular spectra of intensity versus pixel number for the sample. The TE and TM angular spectra are processed to minimize differences between respective regions of the TE and TM angular spectra. The amount of shift in pixels that best overlaps the processed TE and TM spectra is determined. The birefringence B is calculated by multiplying the pixel shift by the index resolution. The stress is calculated by multiplying the birefringence by the stress-optic coefficient.
Abstract:
A lithium aluminosilicate glass-based article includes greater than or equal to 55.0 mol % and less than or equal to 75.0 mol % SiO2, greater than or equal to 1.0 mol % and less than or equal to 18.0 mol % Al2O3, and greater than or equal to 9.0 mol % and less than or equal to 25.0 mol % Li2O. The glass-based article has a thickness less than 0.74 mm, a fracture toughness of the mid-plane composition of the glass-base article is greater than or equal to 0.75 MPα√{square root over (m)}, and a depth of compression that is greater than or equal to 0.14t, where t is the thickness of the glass-based article. The glass-based article is designed to have a single guided mode in the prism coupling spectrum at a wavelength between 360 nm and 405 nm for at least one of the transverse-magnetic or transverse-electric polarization.
Abstract:
A laminated glass article comprises a core layer comprising a core glass composition, and a cladding layer directly adjacent to the core layer and comprising a clad glass composition. A stress of the cladding layer increases with increasing distance from an outer surface of the cladding layer from a compressive stress to a tensile stress, transitions to a compressive stress as a step-change at an interface region between the core layer and the cladding layer, and increases with increasing distance from the interface region to a center of the core layer from the compressive stress to a tensile stress.
Abstract:
A glass exhibiting non-frangible behavior in a region where substantially higher central tension is possible without reaching frangibility is provided. This region allows greater extension of the depth of compression in which fracture-causing flaws are arrested, without rendering the glass frangible despite the presence of high central tension region in the sample.
Abstract:
A laminated glass article comprises a core layer comprising a core glass composition, and a cladding layer directly adjacent to the core layer and comprising a clad glass composition. A stress of the cladding layer increases with increasing distance from an outer surface of the cladding layer from a compressive stress to a tensile stress, transitions to a compressive stress as a step-change at an interface region between the core layer and the cladding layer, and increases with increasing distance from the interface region to a center of the core layer from the compressive stress to a tensile stress.
Abstract:
Chemically strengthened glass articles having at least one deep compressive layer extending from a surface of the article to a depth of compression DOC of at least about 125 μm within the glass article. The compressive stress profile includes a single linear segment or portion extending from the surface to the depth of compression DOC. Alternatively, the compressive stress profile may include an additional portion extending from the surface to a relatively shallow depth and the linear portion extending from the shallow depth to the depth of compression.
Abstract:
Glass-based articles are provided that exhibit improved fracture resistance. The relationships between properties attributable to the glass composition and stress profile of the glass-based articles are provided that indicate improved fracture resistance.