Near speckle-free imaging setup for scattering studies of mirror coatings

Kontos, A.; Loglia, Balthazar; King, B.E.; Dziubelski, Natalia

doi:10.1364/oe.441121

Cited by 5 publications

(2 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The scattering measurements were performed with the setup described in [26]. The samples were placed in two orientations, horizontally and vertically, and the input beam was centered on the interface.…”

Section: Scattering Measurements Of Piecewise Samplementioning

confidence: 99%

Clipping losses from a piecewise coated mirror

Kontos

Loglia

2023

Class. Quantum Grav.

Self Cite

View full text Add to dashboard Cite

The properties of optical coatings play an important role in precision experiments. Gravitational-wave detectors not only require the highest quality coatings but also ones withrelatively large diameters. Coatings made with amorphous material can be scaled up easily but for now exhibit relatively high thermal noise characteristics. Crystalline coatings show great promise in terms of their thermal noise properties but cannot easily scale up to the needed sizes. In this paper we explore the possibility of a piecewise coating that includes both amorphous and crystalline material. Specifically, we estimate the scattering losses of such a piecewise coating as a function of the mismatch in the interface between the two coatings. The calculation should be taken as a lower limit to the total losses, as other surface imperfections will play an important role in the final result, but are not considered here. Finally, we present a measurement of the scattering losses from a piecewise coating, to showcase the challenges of realizing such a design.

show abstract

Section: Scattering Measurements Of Piecewise Samplementioning

confidence: 99%

Clipping losses from a piecewise coated mirror

Kontos

Loglia

2023

Class. Quantum Grav.

Self Cite

View full text Add to dashboard Cite

show abstract

“…To most closely match the use case of coated optics in interferometric gravitational-wave detectors, the setup requires monitoring scattered light from samples illuminated at normal incidence by a light source similar in wavelength to that used by LIGO and Virgo (1064 nm). To avoid time-dependent speckle effects associated with coherent light [10,17,18], thus better allowing association of small changes in scatter with physical changes in the coatings, we use a 1050 nm superluminescent diode (SLD) (e, Thorlabs S5FC1050P, with 50 nm bandwidth and coherence length 𝐿 𝑐 = 𝜆 2 /Δ𝜆 ≈ 20 𝜇𝑚. To monitor fluctuations in the incident power, a few percent of the SLD's output is picked off by a beam sampler (f, Thorlabs BSF10-C) and recorded by a calibrated power meter (g, Thorlabs PM100D).…”

Section: Experimental Setup and Proceduresmentioning

confidence: 99%

Imaging Scatterometer for Observing Changes to Optical Coatings During Air Annealing

Rezac¹,

Martinez²,

Gleckl³

et al. 2022

Optical Interference Coatings Conference (OIC) 2022

View full text Add to dashboard Cite

show abstract

Imaging scatterometer for observing in situ changes to optical coatings during air annealing

Rezac¹,

Martinez²,

Gleckl³

et al. 2023

Appl. Opt.

View full text Add to dashboard Cite

Annealing of amorphous optical coatings has been shown to generally reduce optical absorption, optical scattering, and mechanical loss, with higher temperature annealing giving better results. The achievable maximum temperatures are limited to the levels at which coating damage, such as crystallization, cracking, or bubbling, will occur. Coating damage caused by heating is typically only observed statically after annealing. An experimental method to dynamically observe how and over what temperature range such damage occurs during annealing is desirable as its results could inform manufacturing and annealing processes to ultimately achieve better coating performance. We developed a new, to the best of our knowledge, instrument that features an industrial annealing oven with holes cut into its sides for viewports to illuminate optical samples and observe their coating scatter and eventual damage mechanisms in situ and in real time during annealing. We present results that demonstrate in situ observation of changes to titania-doped tantala coatings on fused silica substrates. We obtain a spatial image (mapping) of the evolution of these changes during annealing, an advantage over x ray diffraction, electron beam, or Raman methods. We infer, based on other experiments in the literature, these changes to be due to crystallization. We further discuss the utility of this apparatus for observing other forms of coating damage such as cracking and blisters.

show abstract

Near speckle-free imaging setup for scattering studies of mirror coatings

Cited by 5 publications

References 37 publications

Clipping losses from a piecewise coated mirror

Clipping losses from a piecewise coated mirror

Imaging Scatterometer for Observing Changes to Optical Coatings During Air Annealing

Imaging scatterometer for observing in situ changes to optical coatings during air annealing

Contact Info

Product

Resources

About