gerne stelle ich euch interessante Diskussionen ĂĽber den FLECHAS-Spektrograph
zur VerfĂĽgung. Da Carlos und Gerardo nicht deutschprachig sind, sind diese BeitrĂ¤ge auf Englisch. Ich hoffe, dass es fĂĽr die meisten im Forum kein Problem ist.
On 23.07.17 22:08, Jan Sundermann wrote:
> Dear Carlos,
> dear Gerardo,
> during your presentation at Aspekte2017 was talk about the
> degradiation of
> optical fibres due to changes of the jacket inner surface.
> For example silver you mentioned, what is highest natural mirror,
> but does react with humidity to change for white oxidation and with
> sulfuric traces in air to become black sulfide surface.
> I then commented, stainless steel should do it also. Basically we have
> two types of stainless steel , the pure chromium steels of high strength,
> and the soft austenitic grades.
> Attached is a brochure of Outokumpu Stainless (in Germany formerly
> Thyssen Krupp Nirosta)
> which shows several grades of surface finish.
> Grade 2R / BA is practically a mirror. And certain stainless
> austenitic steel
> grades should be long time stable to keep such surface.
> It would be interesting to learn, if a manufacturer of optical fibres has
> tested such stainless grades, whose should be avaible as thin foils.
> Or in case, if they see possibility to process such material for a
> test fibre.
> Best regards,
>> During our presentation in Aspekt2017 Gerardo and I talked about the
>> degradation of silver coatings in mirrors, like the parabola collimator,
>> and optionally in echelle surfaces. We did not mention any degradation
>> of silver
>> coatings in optical fibers, where no such coatings are used. Sorry if we did
>> cause such confusion.
>> As for mirrors made of stainless steel instead of glass coated with
>> standard aluminum (>85%), enhanced aluminum (>90%) or silver (>95%)
>> I ignore the reflectivity of stainless steel, but it has also to compete
>> glass in precision polished surfaces, flatness and thermal stability.
>> Carlos Guirao