Agilent 5517B Laser Measurement System

Description

Technical Specifications:

• Laser Type: Dual-frequency Helium-Neon (HeNe) laser
• Laser Wavelength: 632.991 nm (in vacuum, frequency-stabilized)
• Measurement Range (Displacement): Up to 60 meters with optional retroreflector
• Resolution: 0.1 nm (1 Ångström)
• Velocity Measurement Range: 0 to 10 m/s
• Velocity Resolution: 0.1 nm/s
• Accuracy (Linear Displacement): ±0.5 ppm of measured value + 1 nm
• Accuracy (Velocity): ±0.5 ppm of measured value + 1 nm/s
• Output Signal: Quadrature sine/cosine signals (A, B, Z), TTL compatible
• Reference Frequency Output: 10 MHz (disciplined to laser frequency)

Functional Features:

• Dual-Frequency Interferometry: Eliminates direction ambiguity and enables absolute distance measurement
• Real-Time Velocity Measurement: Simultaneous displacement and velocity output from a single laser beam
• Continuous Measurement Mode: Supports uninterrupted tracking of moving targets
• Quadrature Output (A/B/Z): Enables bidirectional counting and homing detection
• 10 MHz Reference Output: Provides a frequency-stabilized reference for external instruments
• Internal Frequency Counter: Built-in high-resolution frequency measurement for velocity calculations
• Analog Output Option: Proportional analog voltage output for velocity or displacement
• RS-232 / GPIB Interface: Supports remote control and data acquisition integration

Performance Parameters:

Material Composition:

• Laser Tube Housing: Stainless steel with hermetic sealing
• Optical Bench: Zerodur or ULE ultra-low expansion glass-ceramic
• Optical Mounts: Invar (nickel-iron alloy) for thermal stability
• Housing Chassis: Aluminum alloy with anodized finish
• Beam Splitter: Dielectric-coated fused silica
• Polarizing Elements: Glan-Thompson or Glan-Laser calcite prisms
• Detectors: Silicon photodiodes with low-noise transimpedance amplifiers

Structural Features:

• Compact All-in-One Design: Laser head, interferometer optics, and electronics integrated in a single unit
• Internal Optical Path: Fully enclosed to prevent air turbulence and dust contamination
• Adjustable Beam Exit Port: Allows alignment flexibility for retroreflector positioning
• Front Panel Controls: Power switch, status LEDs, signal output connectors
• Rear Panel Connectors: RS-232, GPIB (IEEE-488), analog output, power input, trigger I/O
• Vibration Isolation Mounts: Rubber grommets on chassis base for lab bench mounting

Working Principle:
The Agilent 5517B operates on the principle of dual-frequency laser interferometry. Two orthogonally polarized frequencies (f1 and f2, typically separated by ~1.5 MHz) are generated within the HeNe laser cavity using a Zeeman splitter or acousto-optic modulator. The two frequencies travel along the same optical path and reflect off a moving retroreflector. The frequency difference (beat frequency) between the reference and measurement beams is detected by a photodetector. The beat frequency is directly proportional to the velocity of the retroreflector. Integration of the velocity signal yields displacement. The quadrature (A/B) signals are generated by splitting the beat signal into two channels with a 90° phase shift, enabling direction discrimination. The Z (index) pulse provides a once-per-fringe reference for absolute position homing.

Advantages and Highlights:

• Nanometer-Level Resolution: 0.1 nm resolution enables detection of sub-angstrom displacements
• Dual-Frequency Design: Immune to air turbulence and refractive index fluctuations compared to single-frequency systems
• Simultaneous Displacement and Velocity: No need for separate instruments for position and speed measurement
• Long Measurement Range: Up to 60 meters with appropriate retroreflector, exceeding most competing systems
• 10 MHz Stabilized Output: Serves as a primary frequency reference for other metrology equipment
• Low Drift: Frequency stability of ±1 ppm/24h ensures long-term measurement reliability
• Factory Calibrated: Ships with NIST-traceable calibration certificate
• Robust Design: All-metal optical bench with thermal compensation ensures stability in lab environments

Applicable Industries:

• Semiconductor Manufacturing: Wafer stage positioning, lithography alignment
• Precision Machine Tools: CNC machine calibration, linear encoder verification
• Aerospace and Defense: Structural testing, vibration analysis, inertial navigation calibration
• Calibration Laboratories: National metrology institutes (NMI), accredited calibration labs
• Scientific Research: Gravitational wave detection, atomic force microscopy, surface profilometry
• Automotive: Engine vibration testing, chassis dynamometer calibration
• Optical Manufacturing: Lens positioning, interferometer calibration

Model Series:

Installation Requirements:

• Optical Table or Vibration-Isolated Bench: Mount on a table with <1 μm/s² vibration level
• Clean Environment: ISO Class 7 or better (Class 10,000) recommended to prevent dust on optics
• Temperature Control: Maintain ambient temperature within 20°C ± 0.5°C for highest accuracy
• Retroreflector Alignment: Beam must be aligned to retroreflector within ±5 mrad angular tolerance
• Cable Routing: Keep signal cables away from high-current power lines to avoid EMI
• Grounding: Connect chassis ground to building earth ground
• Warm-Up: Allow minimum 30 minutes warm-up before precision measurements

Usage Precautions:

• Do not expose the laser beam to eyes: Class 3A laser, maximum output 1.5 mW, direct eye exposure is hazardous
• Never look directly into the beam exit aperture or retroreflector return beam
• Avoid touching optical surfaces: Fingerprint oils degrade coating performance permanently
• Do not operate in high-humidity environments (>80% RH): Condensation on optics causes measurement errors
• Do not move the unit during measurement: Internal optical alignment is sensitive to shock and vibration
• Do not disassemble the laser head: Sealed HeNe tube requires factory service only; tube life is ~20,000 hours
• Calibrate annually: Send to Agilent/Keysight authorized service center for recalibration to maintain NIST traceability
• Use only Agilent/Keysight specified retroreflectors: Third-party retroreflectors introduce alignment and Abbe error
• Allow warm-up before each use: Frequency stabilization requires ≥30 minutes at ambient temperature
• Store with beam port capped: Use the provided protective cap when not in use to prevent dust ingress