Music

My name is Mathieu, a Phenomenal Antique,

I'm from Mathieu and I'm from Peron.

I'm a joint research unit of the Université de Paris-Dudor,

one of the many private universities,

and the French Seniors.

It's a pleasure to be here.

Maybe you know or you don't know that

the Jewish Semester has a long tradition of excellence in science

but for my French aesthetic, which in my case is very different.

Today I will...

So I do not know exactly which story I should tell you

because it's a serveral school so I'm not at the conference

but I will show you some very recent things that we've been doing,

some older ones and I think there is a chance to see the pedagogical overview

of what I've been doing with my colleagues over the last few years

on the topic of microscale and nanoscale of the mechanical device

and I will present a good part of the talk presenting the center of mass

that we've seen this last year which has been this miniature

of the mechanical disks that we've introduced.

Okay, but first I will still start with a few introductory slides.

Some of them might be redundant, you think that you have already heard

some others not. Anyway, redundancy as you know is the trick for error correction.

It's still good to hear so not the same thing, I just want to hear the different scores.

Two things I would like to say about the interaction between optics and mechanics in general

is that there are several ways that photons can exert a mechanical action on a moving object.

The first way is maybe the most known to you, the most textbook one I speak,

is as a shape of radiation pressure with the well known picture of a photon bouncing back

on a perfectly protecting element. The photon impinges with momentum, H bar K,

as it bounces back it changes the sign on its own way too basically,

so there is a transfer of momentum from that photon to the moving body, a force,

and the moving body gets displaced, it defies mechanical energy.

First thing I would like to make you very note is that this picture actually,

even though you see it everywhere, it's actually incomplete because if the photon,

the impinging photon and the bouncing photon have the same models of their momentum,

so they compare the same energy, and so one can ask oneself the question of where this

mechanical energy gained by a moving body would come from. So this is something to see the question

that we can answer, say exercise since this is the school and we can discuss about that later on.

Second type of interaction which is of importance in many solid state devices is named

heliprostriction. To some people it may be less famous than radiation pressure,

to some engineers it's actually much more relevant than radiation pressure,

and it has a strong connection anyway to radiation pressure. So what's heliprostriction all about?

We have an incoming photon, this time it will go through the material which is at this point

really concerned, but this material has its constitutive atmosphere which can get polarized

under the arrival of this photon, and in a certain class of material it turns out that

this polarizability induces a mechanical strength in the material. This class of materials is called

electroscriptive materials or photomelastic materials or acoustic voltage materials,

as you wish. We're talking about the same thing here, these are materials

used in the arrival of some quantity of electromagnetic energy with the rise of mechanical strength.

Actually there is a deep connection of heliprostriction with optical ray-tranforms and with