Seite 1 © RECENDT 2019 Ivan Zorin

Optical coherence

tomography for non-

destructive testing and

imaging applications

22.01.2019

Ivan Zorin

Seite 2 © RECENDT 2019 Ivan Zorin

General information

Altenberger Straße 69, 4040 LinzTel.: +43(0)732/2468-4600e-mail: office@recendt.atWeb: http://www.recendt.at

SP2, 2. OG

RECENDT: located at JKU in Science Park 2

REsearch CEnter for Non-Destructive Testing

Seite 3 © RECENDT 2019 Ivan Zorin

Research topics and groups

Laserultrasound

Photoacoustic

Infrared-spectroscopy

Terahertz technology

Optical coherence tomography

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Expertise

Quality control and quality assurance for batch production and production controlcontactless control by laser, ultrasound, infrared etc.

Non-destructive testing of materials, contactless analysis and material characterizationfor carbon fiber, composites, metals, etc.

Prototype construction for contactless sensors „From the idea to a marketable product“: by integration of optics, electronics,

µ-processor technology, software (from basic research to a prototype)

Technology- and project management / special projectsSensor development for various areas of application and processes (research-and client-specific-projects)

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Optical Coherence tomographyfor non-destructive testing

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OCT Principle

Common TD-OCT System Axial Resolution:

𝑙𝑐 =2 ln 2

𝜋𝑛∙𝜆0

2

Δ𝜆≈

≈ 0.44 ∙𝜆0

2

Δ𝜆

Probing depth:

𝜔0 ≈4𝜆0𝜋

∙𝑓

𝑑∝

𝜆0NA

𝜆0 – center wavelength

Δ𝜆 – spectral bandwidth

𝑛 – refractive index

Lateral Resolution:

𝑏 = 2𝑧𝑟 = 2𝜋𝜔0

2

𝜆0

Seite 7 © RECENDT 2019 Ivan Zorin

OCT in General

l

PD

BS

M

S

Optical Coherence Tomography

Time Domain OCT Fourier Domain OCT

Spectral Domain OCT Swept Source OCT

lBS

M

S

DG

l

PD

BS

M

S

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Fourier domain OCT

Reference spectrum and raw signal for the mirror in sample

arm (MIR OCT Setup)

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Image formation

Distance ofReference Mirror

EnvelopeA-Scan

Distance ofReference Mirror

A-s

can

Scannen

B-Scan

C-ScanEn-Face

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OCT Scans examples

Pearl

Tape Commercial Thorlabs SystemSub2mu system at RECENDT

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Polarization sensitive OCT

PO

45°

22.5°90°PBS

RFM

BR

λ/4

Line

Detector

2

Line

Detector

1

Reflectivity: 𝑅(𝑧) ~ 𝐴12 (𝑧) + 𝐴2

2(𝑧)

Retardation: 𝛿(𝑧)~ atan(𝐴1(𝑧) / 𝐴2(𝑧))

Δ𝜑 𝑧 ~ 𝜑1 𝑧 − 𝜑2 𝑧

θ 𝑧 =𝜋 − ∆𝜑(𝑧)

2

Optical Axis Orientation:

Reflectivity BirefringenceOptical Axis

orientation

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PS-OCT Scan

Micro-crystallites in turbid materials

Extruded polypropylene with internal defects (micro-crystallites)

PS-Full Field-OCT:

En-face (ac) retardation image (1 x 1 mm x 200 nm)

y

x

P. Hierzenberger et al.; Macro Molecules 47, (2014).

0

π/2

PS – raster scanning OCT:

Cross-sectional (ac) retardation image (5 x 3 mm)

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Ultra High Resolution OCT System

Quality Control in Packaging Industry

Multi-layer foil

Wiesauer et al., Optics Express 13, 1015 (2005)

UHR System at RECENDT

Femtosecond laser/SuperK 800 nm, resolution<2 um, balanced detection, PSOCT

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General OCT projects

Semi-automated thickness measurement of wall-layer-thickness

• Plastic bottle, three layer structure: PP / EVOH / PP• At-line setup for easy measurement at 16 points• New bottle geometries possible• Colours: transparent and red

Challenges:• Straight forward mechanical setup and control• But: layer thickness extraction without trained

personnel• Need for automatic alignment• Other colours not tested

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Research projects

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MORSPEC Main Idea

https://www.teachengineering.org/lessons/view/csu_polymer_lesson01

Morphological information

Spatially resolved chemical compositions

OpticalCoherence

Tomography

Optical Techniques

SRSSpectroscopy

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SRS+OCT

Higher depth penetration because of NIR excitation

Key parameters:

Covered spectral range:

1493 - 2018 cm-1

Spectral resolution ≈ 4 𝑐𝑚−1

Lateral resolution ≈ 10 𝜇𝑚

Acquisition time ≈ 2.5 𝜇𝑠 per

single spectrum

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MID IR OCT

Optical scheme and spectral range

Enhanced Penetration depth has been achieved

Lateral resolution: 35 umAxial resolution: 50 um

Co-registered specta

THIS PROJECT HAS RECEIVED FUNDING FROM THE EUROPEAN

UNION’S HORIZON 2020 RESEARCH AND INNOVATION

PROGRAMME UNDER GRANT AGREEMENT NO. 722380

High power, monochromatic

Non-linear fiber

Broadband supercontinuum

PumpLaser

Supercontinuum Source

• High power • High brightness• Spatial coherence

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MID IR OCT

Multi-layer ceramic sample MIR OCTCommercial Thorlabs NIR OCT

High potential for new types of materials: ceramics, polymers, paints etc.

PolymersMIR OCT Commercial Thorlabs NIR OCT

THIS PROJECT HAS RECEIVED FUNDING FROM THE EUROPEAN

UNION’S HORIZON 2020 RESEARCH AND INNOVATION

PROGRAMME UNDER GRANT AGREEMENT NO. 722380

Seite 20 © RECENDT 2019 Ivan Zorin

MIR OCT Spectroscopy modality

Multimodal mid-IR spectroscopy and optical coherence tomography, WP5

Results: Thermal barrier coating

Averaged spectra

white red green

Lateral position (mm) MIR FD-OCT

Lateral position (mm) NIR FD-OCT

Spectral informationSpatial information

Lateral position (mm)

Absorption (a.u.)

Spectral informationSpatial information

THIS PROJECT HAS RECEIVED FUNDING FROM THE EUROPEAN

UNION’S HORIZON 2020 RESEARCH AND INNOVATION

PROGRAMME UNDER GRANT AGREEMENT NO. 722380

Seite 21 © RECENDT 2019 Ivan Zorin

Diffraction limited Hyperspectral microscopy

Source

Fabry-Pérot Filterspectrometer (FPFS)

PP

VIS microscopic image

Dried blood smear on microscopic glass slide

Measured in reflection

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RECENDT GmbH

Ivan Zorin:

ivan.zorin@recendt.at

Head of OCT:

Dipl.-Phys. Dr. Bettina Heise

Bettina.Heise@recendt.at

+43 / 732 / 2468-4666

www.recendt.at

A – 4040 Linz, Altenberger Straße 69, Science Park 2

Thank you!

THIS PROJECT HAS RECEIVED FUNDING FROM THE EUROPEAN

UNION’S HORIZON 2020 RESEARCH AND INNOVATION

PROGRAMME UNDER GRANT AGREEMENT NO. 722380

Seite 23 © RECENDT 2019 Ivan ZorinTHIS PROJECT HAS RECEIVED FUNDING FROM THE EUROPEAN

UNION’S HORIZON 2020 RESEARCH AND INNOVATION

PROGRAMME UNDER GRANT AGREEMENT NO. 722380

MIR OCT

Bank card, b-scan

Ceramic sample, b-scan