ZYGO 7702 | High-Resolution Interferometer System | In Stock New Original

Description

Key Technical Specifications

• Measurement Principle: Phase-Shifting Interferometry (PSI) & Vertical Scanning Interferometry (VSI)
• Vertical Resolution: <0.1 nm (Sub-angstrom)
• Repeatability (RMS): <1.0 nm (dependent on objective and surface)
• Field of View (FOV): Variable based on interchangeable microscope objectives (e.g., 0.6mm x 0.8mm to 18mm x 24mm)
• Light Source: LED (White Light) for VSI / HeNe Laser (632.8 nm) for PSI (configuration dependent)
• Objective Compatibility: Infinity-corrected Michelson, Mirau, and Linnik objectives
• Z-Axis Travel: Typically 100mm to 200mm motorized stage (for focus and scanning)
• Data Acquisition: High-speed CCD or CMOS camera (10-bit to 12-bit dynamic range)
• Analysis Software: Mx (legacy) or MetroPro (standard), supports ISO 25178 parameters
• Interface: GigE Vision or Camera Link, USB 3.0 for control
• Environmental Sensitivity: Requires vibration isolation table (active or passive)
• Calibration: NIST-traceable calibration certificates available for step heights and lateral scaling

Product Introduction

If you are trying to measure a polished optic, a silicon wafer, or a precision lapped seal face with a caliper or a contact profilometer, stop. You are scratching the part and missing the real story. The ZYGO 7702 setup is what I use when “close enough” gets a batch rejected. It throws interference fringes at the surface and calculates height differences based on light phase shifts. It doesn’t touch the part, so there’s no risk of dragging a diamond tip across a $5,000 lens.The reason this specific configuration stays in demand is its versatility. Whether you need the speed of Phase-Shifting for smooth surfaces or the Vertical Scanning capability for rougher, stepped components, this system handles both without changing hardware. The repeatability sits comfortably under 1 nm RMS, which is critical when your tolerance window is only 10 nm wide. A word of caution: this isn’t a “plug-and-play” tool like a multimeter. If your lab floor vibrates every time a forklift drives by, your data will look like static. You need a solid granite table and isolation legs, or you’re just burning electricity.

Quality SOP & Tech Pitfalls (The Reality Check)

The Lab Report (SOP)
We don’t just ship a box of glass and electronics. Every ZYGO 7702 unit undergoes a rigorous optical alignment check. First, we inspect the objective lenses under high magnification for dust, fungus, or coating delamination—common issues in stored units. Next, we mount a NIST-traceable step height standard and run a full VSI scan. We verify the measured step height matches the certificate within 2%. We also check the laser coherence length and camera linearity. Finally, we run the self-calibration routine in the MetroPro software to ensure the internal reference flat is aligned. You receive a PDF report showing the actual fringe contrast and noise floor measurements, not just a generic “tested good” sticker.The Engineer’s Warning (Pitfalls)
The biggest mistake I see? Ignoring the environment. People spend $50k on this interferometer and put it on a standard workbench next to a running HVAC unit. The vibrations smear the fringes, and the software fails to analyze the data.
Field Disaster Story: A semiconductor fab bought a refurbished 7702 system to inspect wafer flatness. They skipped the active vibration isolation table to save money. Every morning, the first shift got great data. By 10 AM, when the cleanroom fans kicked into high gear, the measurements drifted by 50 nm. They spent three weeks blaming the ZYGO electronics before I showed them a seismograph reading of their table shaking. They bought the isolation table, and the problem vanished instantly. Also, never touch the reference flat inside the objective with your finger. One oil smudge ruins the entire wavefront reference, and cleaning it requires a certified optic technician, not a rag and Windex.

Installation & Configuration Guide

Phase 1: Pre-Installation
⚠️ Site Prep. Ensure you have a dedicated vibration isolation table (air tables are best). The room temperature must be stable within ±1°C during measurement. Drafts from doors or vents will cause air turbulence that distorts readings.
⚠️ Unboxing. Wear powder-free nitrile gloves. Optics are sensitive to skin oils. Inspect all lenses immediately upon opening for shipping damage.Phase 2: Hardware Setup
Mount the interferometer head vertically or horizontally on the stand, depending on your part geometry. Connect the controller box to the head using the proprietary multi-pin cable (do not force it; align the keys). Plug in the camera link/GigE cable to the PC. Connect the power supply. CRITICAL: Ensure the PC has the correct frame grabber card installed if using older Camera Link models; modern GigE units just need a good network card.Phase 3: Software & Calibration
Install the MetroPro (or Mx) software. Run the “System Check” utility. Insert a known flat reference mirror. Adjust the focus until fringes appear. Run the “Reference Flat Calibration” routine. This stores the error map of your specific optics. Save this file; if you lose it, your absolute accuracy is gone. Configure the measurement recipe (PSI vs. VSI, number of frames, noise rejection thresholds).Phase 4: Verification
Measure a calibrated step height artifact. Compare the result to the artifact’s certificate. If the deviation is >2%, re-run the calibration or check for dirt on the optics. Once verified, lock the calibration settings. Document the setup parameters for future operators.

Compatible Replacement Models

Frequently Asked Questions (FAQ)

Q: Can I use this to measure rough surfaces like machined metal?
A: Not directly with standard PSI. If the surface roughness (Ra) is greater than λ/4 (about 150 nm for red light), the fringes break up and the system can’t resolve them. However, if your 7702 is equipped for Vertical Scanning Interferometry (VSI) with a white light source, it can measure rougher surfaces up to several millimeters of range. Check your light source configuration. If you only have a laser, you are limited to polished optics.Q: How often does the reference flat need recalibration?
A: Ideally, once a year. In a clean, climate-controlled lab, it might hold for 18 months. If you see the “fringe quality” metric dropping during daily checks, or if the system was bumped hard, recalibrate immediately. The reference flat is the heart of the system; if it’s wrong, every measurement is wrong.Q: Is the software license tied to the dongle or the PC?
A: Older 7702 systems often use a hardware dongle (HASP key). Newer versions tie licenses to the motherboard MAC address. If you are moving this to a new computer, you must contact ZYGO support to transfer the license. Don’t wipe the old PC until you have confirmed the license transfers successfully. Losing that dongle or license file means buying a new software package, which costs thousands.Q: What kind of maintenance does this require?
A: Mostly cleaning and environmental control. Keep dust covers on the objectives when not in use. Use canned air (held upright) to blow off loose dust. Never wipe a lens unless you see a smudge that air won’t remove, and then only use proper lens tissue and solvent. Check the air table levels weekly. If the bubbles aren’t centered, your isolation is compromised.Q: Can I automate this for production line inspection?
A: Yes, but the 7702 is primarily a lab instrument. For high-speed inline automation, ZYGO offers specific “VeriFire” or automated NewView configurations with trigger inputs and PLC interfaces. You can script measurements in MetroPro, but the mechanical loading/unloading of parts on a standard 7702 stand is manual. Don’t try to rig a robot arm to a standard lab stand without reinforcing the structure; the vibration will kill your measurement repeatability.Q: My fringes are curved even on a flat mirror. Is the unit broken?
A: Probably not. Curved fringes usually mean the system is out of focus or the reference flat isn’t perfectly aligned (tilted). Use the tilt adjustment knobs on the interferometer head to straighten the fringes (null the pattern). If you cannot null the pattern even after adjusting, check for dirt on the reference flat or the objective lens. Only assume electronic failure if the camera shows no image at all.