Fabrication Query

1) Does able to do coating on Aluminium substrate as Aluminium material ?

Aluminium substrate

2) What is the effect of coating for beam splitter in the following cases?

Dear all friends,

I am having a doubt in the following cases of coatings fabricate on 1) multi layer stack coated on flat glass substrate and cemented each other with another flat substrate , measured at 45 degrees incidence.2) multi layer stack coated on flat glass substrate and cemented with a right angle prism and measured 3) multi-layer coating is coated on right angle prism and cemented it with another right angle prism and measured.in all the above 3 cases how the reflectance and peak position will change ? Does the shape of the beam splitter will effect the reflectance?

3) Coating peeling off, How the Stress were generated between the substrate and coated multi layer stack ?

Hi friends,

Recently we have deposited a multilayer stack using materials like TiO2, HfO2 combination and TiO2, Y2O3 combination.both combination of stacks were deposited by electron beam evaporation technique at 200 degrees centigrade.what is the reason behind this….how the grain growth effects the coated film in the case of TiO2/Y2O3 combination.Does the Temperature of the coating is plays a role in the stress generation in the above material combination?

4) How is the adhesion property of the materials for HfO2 and TiO2 on SK2 or Bk7 substrate ?

Hello every one,

I am Vemuri SRS  Praveen Kumar working as Senior Project Fellow in CSIR-CSIO. Recently we have deposited a multilayer optical coatings on SK2 substrate with materials of Tio2 and HfO2 for the wavelength 650 nm in visible region using Electron beam evaporation technique.I have observed that the film after deposited on SK2 material, that the adhesion of the film is very very poor. we have notified that the coating is peeling continuously.can any one suggest what is the reason behind this……

Dear friends
I have fabricated graded filters on glass substrate with 180*150 mm. in different title angle positions.i measured the reflection of each filter. i observed that with increase in angle the roughness is decreasing in x direction , but in y direction the roughness is decreases in extreme right but not in extreme left direction.is there any relation that the roughness will be correlated to the intensity of the filter?

Hi friends,

I am facing problem in the fabrication of dichroic beam splitter, after cementing the two hexagonal prisms the peak shift is happening around 200 nm from the desired peak position.example i considered the design of dichroic beam splitter for 650 nm but after cementing the two prisms the peak shifting around 450 nm. can any one explain  the reason behind this. how to fabricate the dichroic beam splitter.

7) Can any one explain how the harmonics or sidelobes are generated in the thinfilm optical filter?

The basic reason behind the harmonics generation is due to the mismatch of the refractive index variation of the coated film and substrate material.but what is physics behind for the generation of harmonics in optical filter and its significance.

8) How to calculate the Laser Induced Damage Threshold (LIDT) for a Thin film coated sample ?

Hi freinds, i want to measure the thin film multilayer coated sample for testing the laser induced damage threshold.

The substrate  used is BK7 , kindly if any one knows how to measure. please send literature.

9) What are the reasons behind the crystal failures during multi layer coatings?

Dear friends, As we deposited multi layers  coatings in the batch some times the crystal will failure, even if we keep the new crystal, some times it fails. what are the parameters and what precautions should take.

10)  Is there any filter by changing the angle the peak is should not shift to either left or right side?

Through literature i have seen that omni-directional and angle insensitive filter were there.

but in these filters with change in angle, the peak is not shifted in either to left or right.
But the effect of sidelobes were increased. can any one suggest how to overcome these sidelobes in the above filter designs.

11) Present Industry Problems in Optical filters, coatings for next generation projects?

 12) How to do Coating on plastic substrates using ion beam evaporation?

Dear friends, i am interested in optical coatings of plastic substrate, we are using the ion beam evaporation for adhesion purpose and coating has done with electron beam evaporation.

but after the performance of coating on 12 mm thickness PMMA substrate the coating is pealing out. what could be the reason behind it and how to solve this issue.

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