Status Update of the NIST Infrared Optical Properties of Materials Program

Status Update of the NIST Infrared Optical Properties of Materials Program Leonard Hanssen, Simon Kaplan, Sergey Mekhontsev, Vladimir Khromchenko, John Burnett and Jinan Zeng * NIST, Gaithersburg, MD * Now with NASA GSFC CALCON 2015, Logan, Utah, August 25, 2015

Outline 1. Infrared Optical Properties Program Overview 2. Customer Support: Calibration Services & Standards 3. Measurement Systems and Facilities 4. New Capability: Refractometer Extension into the Infrared 5. New System under Development for Additive Manufacturing

FT-IR Spectrometers Fixed λ IR Lasers Infrared Spectrophotometry Overview Tunable λ Measurement Methodologies Ø Error Sources Evaluation Ø Modeling Instruments & Methods Ø Absolute Methods ρ, τ, α, ε, n Materials, Coatings, Optical Components, Cavities & Detectors Direct Measurements & Properties Specialized Accessories Ø Integrating Spheres Ø Goniometer & BRDF Ø Cryostats & Heaters Ø Radiance Comparator Ø Cavity Reflectometer Ø Min. Dev. Refractometer Transmittance Regular Diffuse, BTDF Reflectance Regular Diffuse, BRDF Ellipsometry Absorptance Emittance Polarimetry Quality System Calibration Service Physical Standards Inter-comparisons Reference Data Index of Refraction Extinction Coefficient External: Industry Government Academia Internal: Detectors Sources Materials

Critical Variables Addressed Typical Sample Types Characterized Windows: transmittance / emittance Mirrors: reflectance / emittance Sample Temperature Filters: in-band spectral transmittance & out-of-band level Coatings (especially blacks): diffuse reflectance, emittance Incidence Beam Geometry Cavities & structured surfaces (for blackbodies, radiometers): emittance New (& old) IR optical materials: index of refraction All materials, especially undergoing processing: emittance / reflectance Polarizers: extinction coefficient, Mueller Matrix elements 5

IR Optical Properties Primary Systems Ø Goniometer for Reflectance and Transmittance FTS; Specular, angle, polarization, temperature Ø Reference Integrating Sphere FTS; Diffuse & specular, (near-) normal Ø Spectral Emittance System FTS; Opaque materials, T: 100 C 900 C Ø Bi-Directional Distribution Function (BRDF) Reflectometer (Zeng) Lasers; In- & out-of-plane, 0.785, 1.32, 1.55, 3.39, 3.9-4.1, 4.9-5.1, 9.2-11.2 µm Ø * Cavity Reflectometers (Zeng) Lasers; Cavity apertures from 3 mm to 200 mm dia. Ø Refractometer for Index of Refraction (Burnett) Monochromator; 0.12 µm to 14 µm Ø ** Hemi-ellipsoid Reflectometer FTS; Spectral extension to 100 µm for diffuse materials Ø ** TEMPS Facility for Additive Manufacturing Support (w/ Intelligent Systems Division) FTS & ; Temperatures up to 3500 K 6 * Upgraded Capability New Infrared Capability ** Under Development Capability

Infrared Spectrophotometry Calibration Service Technical Contacts Calibration Areas Policies NVLAP Quality System Traceability NIST Home > Calibrations > Optical Properties of Materials OpAcal ProperAes of Materials Measurements Technical Contacts: Leonard Hanssen (38075S) Tel: 301-975- 2344 E- mail: leonard.hanssen@nist.gov Simon Kaplan (38075S) Tel: 301-975- 2336 E- mail: simon.kaplan@nist.gov Special Tests of Infrared Reflectance, Transmi6ance, and Emi6ance of Materials (38075S) Measurements of infrared spectral reflectance, transmi4ance, and emi4ance can be made for the wavelength region 1 μm to 20 μm (50 μm for transmi4ance) for submi4ed test items. In general, measurements are performed on test items with dimensions from 1 cm to 7.5 cm perpendicular to the incident beam. measurements can be performed in specular, diffuse, direceonal- hemispherical, and bidireceonal distribueon funceon (BRDF) geometries. CapabiliEes also exist for performing variable temperature measurements, with emi4ance measurements available from room temperature to 900 ºC. Uncertainty esemates are provided, and depend on the opecal characterisecs of the submi4ed test item and the instrument used to perform the measurement. Arrangements for measurements on submi4ed test items must be made before shipment. The decision to perform the measurements and seleceon of the instruments to be used rests with NIST. 8

Satellite Instrumentation Supported by Calibrations

SRMs 1928 & 1929 Gold Mirror Reflectance Standards (under calibration process) SRM 1928: 2 dia. SRM 1929: 1 dia. Electroplated gold over polished copper substrate Calibrated for near-normal spectral reflectance From 2 µm to 17 µm Anticipated expanded (k=2) uncertainty: 0.25% Anticipated availability: 2016 10

SRM 2038a Diffuse Infrared High Reflectance (under development) Electroplated gold over laser etched nickel substrate (replicable) Calibrated for near-normal-hemispherical spectral reflectance From 2 µm to 17 µm Anticipated expanded (k=2) uncertainty: 1.5% Anticipated availability: 2017 11

Primary NIST Infrared Spectrophotometry System for Reflectance and Transmittance Infrared Gonio-Reflectometer Transmissometer (IGRT) Infrared Reference Integrating Sphere (IRIS) 13

Infrared Reference Integrating Sphere (IRIS) Sphere Specifications λ range: 1.0 18 µm 15 cm diameter Gold-plated plasma-sprayed metal coating MCT detector w/ concentrator optics Spot size 2-10 mm 8 incidence angle System Capabilities Reflectance, Transmittance, Absorptance & Emittance Temperatures 15-200 C absolute & relative, specular & diffuse Ø R & T direct Ø A & E indirect uncertainties (2s): Ø specular: 0.3% Ø diffuse: 1.5-3.5% Ø larger for angle dependent structure can measure R of transparent samples can sort out scatter from total R & T

Infrared Spectral Emittance System Upgrade Heated Sample and Sphere Ø FT Based Based Spectral Radiance Comparator (includes Near IR Sphere) Ø Purge, polarization; λ range: 1 µm - 50 µm; T range: 200 C 900 C Ø Improved S/N with upgrade of Bomem DA 3 to Bruker V80(70)v - completed Ø Installed T-controlled background for sample -> lower T capability 15

IR Bi-directional Reflectance Distribution Function Instrument Detector Unit I Sample Beamsplitter Goniometer Sample rotation Detector Unit II Half waveplate Polarizer-analyzer attenuator Folding mirror Detector rotation Z Filter Wheel Spatial filter X Y Folding mirror Stabilized CO 2 Laser BRDF = dp s P i dω cosθ s

CHILR-II Complete Hemispherical Infrared Laser Reflectometer for Cavity Absorptance / Emissivity CHILR I 20 cm dia. Sphere Port Reducer & Reference Wheel Input Laser Beam Rotatable input Slot CHILR II 50 cm dia. IR Sphere Liquid Bath Test Blackbody Y-Scan Stage Black Target for Dark Level 17

CHILR Calibration Examples: IR Effective Absorptance/Emissivity (at IR Wavelengths (1.32, 3.9, 4.9, 7.3, 10.6 µm) Ø Radiometer Cavities SORCE Total Irradiance Monitor Active Cavity Radiometer Irradiance Monitor III NIST Pico-Watt Absolute Cryogenic Radiometer Ø Blackbody Cavities NOAA JPSS CrIS Internal Calibration Target Blackbody NASA CLARREO Demonstration System Low T, Cold Source and Variable T, Blackbodies NIST IR Radiance & Temperature Facilities Transfer Standard Blackbodies 18

Hemi-ellipsoidal Reflectometer w/ Large Area Pyro Detector Input Beam Detector Sample - Alternative to Integrating Sphere - Potential to 100 µm 19

IR Index of Refraction Program In 2013 IR community request NIST to support infrared index of refraction standards support: letter from SPIE Infrared Material Standards Working Group (IRMWG) + President Arthurs) Positive response from NIST Director & decision to pursue IR index capability Goal - achieve highest possible accuracy for index of important IR materials Goal provide traceability for IRMWG Round Robin, obtain standard data Upgraded UV-vis Min-Dev refractometry facility, extending λ to 14 µm. Through IRMWG, Materials Vendors providing prisms for analysis Materials: Ge, ZnSe, ZnS, Si, CaF 2, BaF 2, As 2 Se 3, GASIR1, etc. Ge measurements recently begun. 21

NIST VUV to IR Refractometry System Features All reflective optics + purged housing Spectral range: 120 nm to 14 µm (monochromator). Temperature range - operates normally near room T (15-25 C). Goniometer - absolute angle uncertainty 0.2 arc-sec. Temperature control of sample to 5 mk, purge gas to to 20 mk. Index Uncertainties: VUV/vis (0.12 0.8 µm): 1-σ ~ 5 10-7 - 5 10-6 Near - Mid IR (0.8 5.0 µm): 1-σ ~ 5 10-6 - 4 10-5 Mid LW IR (5.0 14 µm): 1-σ ~ 4 10-5 - 8 10-5 22

Additive Manufacturing (3D Printing): Various Processes Involving Fast, High Intensity Laser Melting of Metals & Ceramics Time Exposure Showing Laser Scan Path Selective Laser Melting Process Part Made Layer by Layer Need for Temperature Monitoring & Control; need for & Emittance Data. 24

AMMT/TEMPS Project Ø Build state-of-the-art facility with controlled laser heating of materials, process diagnostics and metrology instrumentation, with dual functionality: Advanced Manufacturing Metrology Testbed (AMMT) Intelligent Systems Division Ø A Selective Laser Melting (SLM) machine (AMMT) Ø Flexible control of laser power, beam size and scan pattern Ø Representative of industrial systems; laser power, scan speed, positioning accuracy, etc. Ø Facilitate process diagnostics, monitoring and control using in-line, staring and off-line tools. Ø Study methods for real-time process thermometry in the production environment, and effects of real time process control on the build quality, develop optimization methods Temperature and Emittance of Melts, Powders and Solids (TEMPS) Sensor Science Division Ø A primary standard facility (TEMPS) for optical and radiative properties of materials (powder, solid & liquid form) at solid and liquid-phase temperatures, static & dynamic Ø Measurement of the in-situ SLM process temperature with high accuracy Ø Measure temperature distributions across and around the melt pool Ø Obtain spectral reflectance and emittance of various materials Ø System can obtain data applicable to many High Energy Laser Matter interaction processes 25

Critical Optical Property Measurement Parameters & Potential for new Standards, Reference Data and Calibration Services Temperature 3500 K 2000 K Material Form Sample Environment Vacuum High Purity Gas 1175 K 295 K 4 K Dry Air 30 µm Solid 10 µm Powder Liquid Sintered Wavelength Others: Polarization, Geometry (spot size, direction angle, hemispherical), etc. Current 1 µm 350 nm New, w/temps

TEMPS Facility for Temperature, Emittance of Materials 27

Summary & Comments NIST s IR Optical Properties of Materials Program supports a wide range of external customers as well as other NIST groups activities through materials, sources and detector characterization & calibration. We strive to continuously improve and expand our capabilities to address new and emerging needs, within the allocated resources (funding and labor) available to us. Ongoing input and support from our customers, their communities and organizations, are critical to maintaining internal support for our Program. 28