Photo Research PR-745 Spectroradiometer

Overview

The Photo Research PR-745 Spectroradiometer is a high-sensitivity, thermoelectrically cooled scanning spectroradiometer engineered for precision measurement of spectral radiance across the visible and near-infrared (NIR) spectrum—from 380 nm to 1080 nm. Based on grating monochromator architecture with a back-thinned, deep-depletion CCD detector, the PR-745 delivers exceptional signal-to-noise ratio (SNR) at low light levels—critical for evaluating NIR-emitting devices such as VCSELs, IR LEDs, night-vision displays, and automotive LiDAR emitters. Its optical design minimizes polarization sensitivity and stray light contamination (<0.05% typical), ensuring traceable, repeatable measurements under demanding laboratory, production-line, or field-deployable conditions. Unlike broadband photometers, the PR-745 captures full spectral power distribution (SPD) at native resolution, enabling rigorous CIE-compliant colorimetric, radiometric, and photometric analysis without interpolation or filter-based assumptions.

Key Features

• Thermoelectrically cooled CCD detector for stable dark current suppression and enhanced low-light sensitivity—20× more sensitive than the PR-735 at equivalent integration times
• Ultra-fast spectral acquisition: up to 250× faster than PR-735, enabling high-throughput QA/QC in manufacturing environments
• Three programmable spectral bandwidths (4 nm, 8 nm, 14 nm) with automatic selection—optimized for trade-offs between resolution, throughput, and SNR
• AutoSync® real-time synchronization technology eliminates temporal artifacts during flicker-sensitive measurements (e.g., PWM-driven displays or pulsed IR sources)
• Eight precision-machined field stops for calibrated radiance measurements across spatially heterogeneous sources (e.g., micro-LED arrays, OLED subpixels)
• Integrated full-color touchscreen interface with onboard data visualization and SD-card logging—no PC required for basic operation
• Modular connectivity: USB 2.0 standard; optional RS-232 serial and Bluetooth 4.2 for wireless telemetry and remote control
• Rechargeable lithium-ion battery pack supporting 8 hours of continuous operation—ideal for portable metrology in cleanrooms, R&D labs, or outdoor photometric surveys

Sample Compatibility & Compliance

The PR-745 accommodates diverse emission geometries and source types via a comprehensive suite of NIST-traceable optical accessories—including MS-75 telecentric lenses for narrow-angle radiance, IS-730 integrating spheres (for LED flux calibration), LR-730/LR-127 LED intensity analyzers, CR-730 cosine correctors (for irradiance), and RS-3/SRS-3 calibrated reflectance standards. All accessories are mechanically and optically registered to maintain system-level uncertainty budgets. The instrument meets foundational requirements for ISO/CIE 12647, ASTM E308-22 (computation of tristimulus values), and IEC 62471 (photobiological safety). When operated with SpectraWin 2® under controlled user permissions and enabled audit logging, the system supports FDA 21 CFR Part 11 compliance for regulated environments requiring electronic records and signatures.

Software & Data Management

SpectraWin 2® is a Windows-native application providing full instrument control, real-time spectral visualization, and advanced post-processing. It computes and exports over 40 standardized metrics per measurement—including luminance (cd/m², fL), spectral radiance (W·sr⁻¹·m⁻²·nm⁻¹), chromaticity coordinates (CIE 1931 xy, 1960 uv, 1976 u′v′), correlated color temperature (CCT), Duv, CIELAB/CIELUV, ΔE*₀₀, dominant and peak wavelength (0.1 nm resolution), and radiant/photopic power integrals. Raw SPD data is saved in ASCII and binary formats for third-party analysis (MATLAB, Python, Origin). The software enforces role-based access control, time-stamped audit trails, and immutable data archiving—fully compatible with GLP and GMP documentation workflows.

Applications

• Characterization of NIR emitters: VCSELs, IR LEDs, thermal sources, and laser diodes used in sensing, biometrics, and autonomous systems
• Display metrology: OLED, microLED, and Mini-LED panel uniformity, white point stability, and dimming response under variable drive conditions
• Automotive lighting: Headlamp beam pattern validation, adaptive driving beam (ADB) spectral fidelity, and interior ambient lighting compliance
• Material reflectance and transmittance: With RS-3/SRS-3 standards and ICC-730 integrating sphere, supports ASTM E903 and ISO 9050
• Photobiological safety testing: Spectral weighting per IEC 62471 for retinal blue-light hazard and IR exposure assessment
• Calibration transfer: As a reference-grade spectroradiometer, it serves as a primary standard for field instrument verification and inter-laboratory comparison

FAQ

What is the calibrated spectral range of the PR-745?
The PR-745 is factory calibrated from 380 nm to 1080 nm, covering the full visible band and extending into the short-wave near-infrared (SWIR) region.
Does the PR-745 support automated compliance reporting for ISO or ASTM standards?
Yes—SpectraWin 2® includes built-in templates for ASTM E308, ISO/CIE 15, and CIE 13.3, generating compliant reports with traceable uncertainty budgets and metadata.
Can the PR-745 measure pulsed or modulated light sources accurately?
Yes—the AutoSync® function locks acquisition timing to external trigger signals or internal zero-crossing detection, eliminating aliasing and enabling precise duty-cycle-resolved spectral analysis.
Is NIST-traceable calibration included with the instrument?
Each PR-745 ships with a NIST-traceable calibration certificate valid for 12 months, covering radiance, wavelength, and linearity across its operational range.
How does the PR-745 differ from the PR-740 model?
The PR-745 extends spectral coverage to 1080 nm (vs. 780 nm for PR-740) and uses an optimized optical path with reduced stray light—making it the preferred choice for NIR radiance applications where spectral purity is critical.