Reef-RT Autocorrelator by Hengjiu

Overview

The Reef-RT Autocorrelator by Hengjiu is a precision optical instrument engineered for time-domain characterization of ultrashort laser pulses in the near-infrared spectral region. Based on second-harmonic generation (SHG) interferometric autocorrelation, it enables direct measurement of pulse duration without prior knowledge of spectral phase—making it ideal for rapid diagnostics in R&D and industrial laser development environments. Designed for operation across two complementary wavelength bands (700–1000 nm and 1000–1400 nm), the Reef-RT supports characterization of Ti:sapphire, Yb-fiber, Er-fiber, and Tm-fiber lasers commonly used in telecommunications, ultrafast spectroscopy, and nonlinear optics laboratories. Its robust mechanical architecture ensures alignment stability under ambient lab conditions, while its compact footprint facilitates integration into existing optical tables or OEM laser systems.

Key Features

• Interferometric SHG autocorrelation design with adjustable delay line and high-damage-threshold BBO or KDP crystals optimized for both sub-100-fs and picosecond-scale pulses
• Dual-band spectral coverage: independently calibrated configurations for 700–1000 nm and 1000–1400 nm, enabling seamless transition between common ultrafast laser sources
• Flexible triggering architecture supporting single-shot (1–10 Hz) and multi-shot (>10 Hz) acquisition modes, compatible with low-repetition-rate amplified systems and high-repetition-rate oscillators
• Input energy sensitivity down to 50 nJ at kHz repetition rates—enabling reliable measurements without external amplification or attenuation stages
• Linear polarization input acceptance (horizontal or vertical), with integrated waveplate mount option for polarization optimization
• Modular optical path design allowing field-upgradable components, including motorized delay stages and USB-powered CCD readout interfaces

Sample Compatibility & Compliance

The Reef-RT accommodates free-space collimated beams with diameters up to 8 mm and divergence < 1 mrad. It requires no beam splitting or cavity coupling, minimizing insertion loss and preserving pulse integrity. All optical coatings meet ISO 10110 surface quality standards; crystal substrates comply with MIL-O-13830 scratch-dig specifications. The system adheres to IEC 61000-6-3 (EMC emission) and IEC 61000-6-2 (immunity) requirements for laboratory instrumentation. While not certified for medical or aerospace-grade qualification, its performance traceability aligns with NIST-traceable calibration practices for metrology-grade pulse characterization in GLP-compliant environments.

Software & Data Management

The Reef-RT operates via Hengjiu’s proprietary AutocorrStudio software (Windows 10/11, 64-bit), providing real-time interferogram acquisition, background subtraction, FWHM/Gaussian deconvolution analysis, and pulse width trending over time. Raw interferograms are saved in HDF5 format with embedded metadata (wavelength, repetition rate, crystal type, delay step size). Export options include CSV, PNG, and MATLAB .mat files. Audit trail functionality records user actions, parameter changes, and calibration timestamps—supporting basic 21 CFR Part 11 compliance when deployed with domain-authenticated Windows accounts and enabled file-integrity logging.

Applications

• Characterization of femtosecond fiber lasers in telecom C- and L-bands (1530–1625 nm equivalent via frequency-doubled detection)
• Diagnostic validation of chirped-pulse amplification (CPA) systems before and after compressor alignment
• Monitoring pulse stability in ultrafast oscillator cavities during environmental drift studies
• Education and training in ultrafast optics laboratories, where intuitive alignment and deterministic interpretation support pedagogical objectives
• Pre-shipment verification of OEM ultrafast modules intended for integration into OCT, LIBS, or multiphoton microscopy platforms

FAQ

Does the Reef-RT provide full phase reconstruction (e.g., FROG or SPIDER)?
No—the Reef-RT performs intensity autocorrelation only. It reports pulse duration assuming Gaussian or sech² temporal profiles; spectral phase retrieval requires complementary techniques.
Can it measure pulses outside the specified wavelength ranges?
Operation beyond 700–1400 nm is not supported due to crystal phase-matching limits and detector quantum efficiency constraints.
Is external synchronization required for multi-shot mode?
Yes—a TTL-compatible trigger input is mandatory for stable averaging at repetition rates above 10 Hz.
What maintenance is required for long-term accuracy?
Annual verification using a reference 100-fs Ti:sapphire oscillator is recommended; no consumables or recalibration fees apply under standard use conditions.
Is the system compatible with vacuum or UHV environments?
No—the Reef-RT is designed for ambient atmospheric operation; vacuum-compatible variants require custom engineering and are available upon request.