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Femtosecond laser writing of glass, including borosilicate, sulfide, and lead

36 points| peter_d_sherman | 5 years ago |patents.google.com | reply

12 comments

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[+] ximeng|5 years ago|reply
Effectively this is a way of producing optical waveguides by using lasers to adjust optical properties of glass blocks. It uses less energy than previous methods to achieve similar or better results (speed, focus).

Key phrases:

Such a method could be used to write continuous light-guiding waveguide patterns connecting any two points within a continuous block of a suitable material, or make other optical devices, such as Bragg gratings

https://en.m.wikipedia.org/wiki/Fiber_Bragg_grating

While the mechanism of the interaction of the glass with the fs-laser is not clear, it is believed that because of the shortness of the pulse duration, the excited photo-electrons cannot thermally relax since the pulse duration is shorter than the lattice thermalization time. With high enough intensities and the inability for the electrons to relax, one can build up a relatively high electron density. It is sufficiently high to be considered a plasma. (A plasma is a collection of electrons essentially acting as a free electron gas). How the structure is permanently changed as a result of this is not known.

The invention can also be used to make interferometers or phased arrays. Also, integrated optical waveguide devices in a single glass body which utilizes multiple optical waveguide structures and paths integrated and combined together to manipulate and operate on light transmitted through the glass, such as performing a function of an inputted optical waveguide channel and an integrated optical waveguide devices which separates/combines optical waveguide channels based on wavelengths, can be made.

[+] wallwart|5 years ago|reply
Can this also be used for data storage in a 3D medium? It references a patent from 1991 on this, not sure how far things have come since then.
[+] mfgs|5 years ago|reply
Some interesting photos of what's possible with that technique: http://optofab.org.au/uli.html
[+] Prcmaker|5 years ago|reply
I've used a few FBGs from them. They were so good we had to introduce a lot of loss to avoid saturation.
[+] andy_ppp|5 years ago|reply
Looks really interesting, does this mean thinner, flatter better phone camera lenses?
[+] cycomanic|5 years ago|reply
No, you just write structures into glass. I think you could write fresnel lenses, but I suspect performance would not be great. If you want flat lenses you should look at what is being done with metasurfaces.
[+] Gravityloss|5 years ago|reply
You could make the lens / microlens array for a light field camera with this.
[+] CamperBob2|5 years ago|reply
A Rotman lens might be interesting as well.